The Validity of High-Fat or High-Carb Diets on Endurance Exercise...
Or is it just an excuse to overindulge?
Recently,
a myriad of “scientifically proven” diets and exercise regimens have been
broadcasted on television or “pushed” by trainers and fitness centers, claiming
to increase endurance, muscle mass, and weight loss. In a July 2012 Nutrients article by Murakami et
al, the investigators looked at the effects of high-carbohydrate diets (“carb-loading”)
and high-fat diets on endurance performance. The article can be found at the hyperlink below:
For Biochemistry extra credit on Exam II, the exam that
included the chapter on carbohydrates, I want you to read that article and
provide an in-depth critique of its validity.
First, you should summarize the paper and their findings. Then, you should provide the actual
critique. Do you agree or disagree (or
even partially agree) with the authors?
What assumptions are they making?
Are their conclusions valid based on the actual data or are they
overstated? Are there any discrepancies
in the data? What are the limitations on
how they actually set up the experiments?
What would you do differently?
And so on….
The
critique should be at least 500 words.
Feel free to cite other sources.
Many athletes implement the idea of “carb loading” prior to a major competitive event. However, one of the greatest questions that rises in my mind is how effective is this at producing a larger amount of energy? One of the main points I wanted to highlight from the article was the importance of incorporating both the HFM and the HCM methods. According to the article implementing both methods will enhance energy performance. Glycogen can reach a peak level after which any additional carbs will no longer be absorbed making “carb loading” beneficial only up until a certain point. Carbohydrate after glycogen levels have been maxed out may result in FFA immobilization. The inability for FFA to be metabolized may result in the rapid depletion of glycogen resulting in a decrease in performance level. The overall decrease in performance level may highlight one of the main issues concerning the sole use of HFM as an energy source. Though glycogen storage is a great short-term energy source, FFA metabolism may be better suited for endurance performance. The characteristic long carbon—hydrogen linkages of FFA are extremely energy rich making FFA more suitable for high-energy activities for an extended period of time. The main focus of the article was to, “investigate the effects of a HFM and a HCM 4 h prior to exercise after ingesting a high-carbohydrate diet for 3 days, based on previous studies, and to demonstrate the effects on endurance performance from ingesting carbohydrates immediately before exercise in subjects that have ingested a pre-exercise HFM.”
ReplyDeleteIndirect calorimetry was used to calculate the respiratory exchange ratio (RER). RER is very important in glucose and fat metabolism.1 According to Figure 3 of the article athletes who participated in the HCM + P group yielded the most energy from carbohydrate oxidation during both the rest and exercise periods. HFM + P and HFM + M subjects had similar carb oxidation levels during the resting period. However, a significant increase in HFM + M group was observed during the exercise period. This finding alone is inconsistent with the medically accepted idea of fat producing more energy than carbs. Later on the article noted that when HFM was coupled with maltodextrin jelly, a carb, the subjects’ were able to exercise for a longer period of time. Therefore, it could be concluded that carb and fat coupling may result in an overall increase in endurance. As the FFA from the HFM is used up during a work out, the body is able tap into its carb (glycogen) reserve. This reserve enables the body to maintain energy production and endurance levels necessary for extended periods of exercise.
In my personal opinion, it makes complete sense and the findings in this article are scientifically sound. It justifies why athletes carb-load while highlighting another key element that has and continues to be overlooked… fat. Because many health buffs see fat as bad thing they fail to consider the benefits of incorporating it into their pre-workout regimen. Though overall, I do agree with their findings, one of the things that got me was the way they stated, “this study do not confirm the findings of several previous studies…” Such a discrepancy like the carbohydrate levels of the subjects prior to the experiment may have detrimental effects on the results. Therefore, if this were my experiment I would indefinitely document the pre-experiment carbohydrate, fat and insulin levels of all of the subjects.
References
1. The importance of Respiratory Exchange Ratio in Fat Loss. Available at: http://www.powerstrengthfitness.com/index.php?option=com_content&view=article&id=57&Itemid=55. Accessed: November 13, 2012.
Nice job, Jessica.
DeleteAfter reading the article the author seems to be stating that they were investigating the effects of both HFM and HCM prior to exercise. This article also displayed the effects of endurance performance from ingesting carbohydrates immediately before exercise when a person has ingested pre-exercise HFM. This article conducted an experiment that evaluates high fat and high carbohydrate diets prior to endurance running test. They tested eight different collegiate athletes that participate in physical training for the investigation. Test results from the article indicated that the individuals that were on the HFM showed extended levels of exhaustion, while individuals that are on the HCM showed no special results. However, there were two significant findings presented in the study. The first finding was the fact that glycogen loading can enhance the endurance running performance of athletes. The second finding was the HFM lowering of carbohydrate oxidation. However, in response to this article I disagree with this article finding. I am an athlete and I have never believed in carb- loading. Personally I feel that this article is a little exaggerated because of the fact that they only test eight males for this experiment. I believe that all people are different and respond different to different diets. The reason that I think that this study is an overstatement is because there were no females or older subjects investigated upon. So initially this study is already overstated to say overall that all people have a positive response to the glycogen loading. I think that this article is making assumptions about an overall result for people but they only have tested the male subjects. For example the article states that “a HFM and subsequent ingestion of a small portion of carbohydrate jelly prior to exercise enhances the performance of athlete endurance running.” This is a general statement that only refers to the subjects tested. The discrepancies presented in this article were when the author stated “results were not demonstrated in human studies, with studies failing to show a difference in exercise performance between the consumption of a HCM and HFM. Overall I think that I agree with this study when referring to the subjects that they tested but not with the extended statement referring to an entire group of people. Additionally, I think that this diet can be helpful and effective to some people but I don’t believe that it is effective to all. Furthermore there is sufficient information presented throughout the article but I do believe that the study is a little exaggerated. According to the article the HFM and the HCM are efficient with the subjects tested in the article but they are too focused on just those subjects. Yet the article was beneficial to learn about the effects of macronutrient composition.
ReplyDeleteIn conclusion if I could do this experiment differently I would definitely change the subjects that were tested. I would have more than eight subjects and I would choose a variety of different subjects to represent the information presented in the study. I believe that the study is a little too focused on the male subjects in the study.
Good job, Nadia. I like how you have related it back to your personal experiences.
DeleteApparently my post was too long, so I cut out the summary. I emailed my entire assignment to you. Here is my critique.
ReplyDeleteCritique
I first want to begin by saying that I think this was an interesting study. I always hear a lot about “carbo-loading” the day before a game or even a test, but I always wonder if it truly works, or if something might work better. There are so many serious athletes in the world that research like this can be very useful to them. However, I do not think that the conclusions derived from the data are acceptable. I also do not think that the experiment was well constructed/run. My first comment is that there are only 8 subjects, all of which are collegiate long distance runners. Endurance is important in sports other than long distance running, and long distance runners have different muscle types that short sprinters. I think it is important that another group of athletes is considered for this experiment. There also needs to be many more subjects than eight. That is definitely not enough subjects to derive legitimate conclusions from. The margin of error is too large for that few subjects. My second comment deals with the jellies consumed just before exercise. I was frustrated that the authors did not really describe the reasoning behind the jelly consumption until the end of the paper. It should have been explained more thoroughly, and the placebo jelly should have been more defined. For all I know, the placebo jelly and maltodextrin jelly can be very similar. Also, why was there not a fourth meal that included the maltodextrin jelly with the high carbohydrate meal? Regardless of the purpose of the jelly, there should be that fourth meal in order to keep the experiment balanced and controlled. Thirdly, I want to address the actual data about how much time it took for the subjects to reach exhaustion depending on what test meal they had. The standard deviation of some of the tests actually overlaps a little bit, and if they do not overlap, then they are really not that different. For example, the high fat meal plus the placebo jelly has an average of 92 plus or minus 2.8, while the high carbohydrate meal plus the placebo jelly has an average of 90 plus or minus 1.7. If you take the minus of the first one and the plus of the second, then the numbers are identical. The high fat meal with maltodextrin jelly has a higher average but a larger standard deviation. The large standard deviation is basically used to make the data look better. The differences in the data are really only about 3%-5%. Without even looking at any of the other data, it seems like the authors of the paper tried to slightly manipulate the data to make it support their hypothesis.
The few aspects of the experiment that I thought were constructed well included the high amounts of parameters the authors looked at, and the protocol for the experiment. It was really good that the authors looked at glucose levels, free fatty acid levels, insulin, lactic acid, and the oxidation of carbohydrates and fats. However, I did not understand why the lactic acid data was taken from blood from the ear lobes, and I did not see if they explained it. In the end, I think that this is a cool study that needs a little help. The data can be very useful, but definitely needs to be taken to a higher scale with more subjects, as well as a more consistent and more defined experiment.
In this article, researchers are debating on whether a diet high in fats right before exercise is better for you as opposed to a diet in high in carbohydrates right before exercise. They gathered some male college athletes and fed them a high carbohydrate meal for three days prior to their experimented race. Next, the group was split; half of the men ate a high carbohydrate meal four hours before the race while the other half ate a meal high in fats right before their race. Of the men who ate the fat meal, half of them were given maltodextrin jelly in addition to the meal. The left over men were given a placebo jelly. To test these two diets, the subjects were all required to run until exhaustion. The researchers wanted to see if those who ate the fat meal could run longer than those with the carbohydrate meal. Their blood and exhaled gases were also examined to understand the biological properties of this experiment better. In the end, it seemed that those with the high fat meal with the maltodextrin jelly lasted longer in their runs without becoming exhausted.
ReplyDeleteI personally agree with what the article says, but with some skeptics. I honestly have always heard that carbohydrates were better for you before a race in order to perform well. Subway is one of the main sponsors of the Olympics. They claim to fuel the Olympic athletes well. I’ve never heard of anyone ever saying to eat a lot of fat right before the race. I feel like that would cause me to throw up! I’m also skeptic because they even told us in the paper that these findings contradicted what other research has said. Their only reason for saying that their experiment is different was the type of exercise; they measured exhaustion in long distance running. I also do not understand why they use maltodextrin jelly. I don’t think this was ever stated. Also, why do they not use it in the carbohydrate group. One more thing I would like to know in their data is what the actual food was that they were given. What kind of fats did they use. I’d also be interested in understanding the biochemistry behind it. They mentioned that the fats caused glucose to be expended slower, but why did that happen? I’d be interested in trying this for myself to see if it worked better for me. I wonder what the results would be if they used females; would it be different at all? Some data that I found a little far-fetched was what was found in table 2. The times of exhaustion are not too far off from each other; some are actually only a couple minutes different. I do not think this is big enough of a time difference to claim that fats are definitely the better option.
First off, I thought this paper was very well done, with many good things about it. One good thing was the level of testing that was performed on the athletes before the testing was done, while undergoing the rest period, and even through the exercise time. These different tests, such as maximum oxygen intake, onset of blood lactate accumulation, and various spirometer tests which calculated the oxygen and carbon dioxide fractions. Another thing that was well done in the experiment was the selection of the test subjects. They were all relatively the same build, and natural and physical ability (in my mind I pictured 8 identical Spartan brothers from 300).
ReplyDeleteHowever, there were many parts of this experiment that I thought were off or could have been improved on, to strengthen the study. The first thing I noticed was the use of the placebo/marmalade jelly that was taken three minutes prior to the trial exercise. I understand from finishing the paper, that it was used as a source of carbohydrates to see if there was a correlation between having carbs in the subjects system just prior to the trial run. I realize that the jelly wasn’t used in the subjects who had already ingested a HCM prior to the trial run, but they should have had a meal that also consisted of the HCM with the placebo jelly. The subjects could basically tell (at least I could) from the different meals each time they were a part of the experiment what was different and what wasn’t. Another quarrel I had with the experiment was the group size and setting. They only tested 8 men, who were in long distance running shape. I agree that this was necessary for the experiment as they were testing the endurance of long distance runners, but I would have liked to see a possible follow up experiment or even a concurrent/addition to this experiment showing different runners or athletes of differing weights, sizes, and level of athleticism. Also about the setting of the experiment, it was performed in a laboratory at a controlled pressure and temperature. Real athletes, who run marathons, do not run in laboratory settings, so this may have changed the dynamics of the experiment compared to real world marathons, as the sun and wind could affect the athletes as well. Finally, the results that they attempted to present as fact that the experiment supported their hypothesis wasn’t really that strong. The times that the runners ran until exhaustion were in fact better with the HFM, but only barely. In some situations, the times were a couple minutes off and including the standard error, even made the HCM more effective that the HFM.
So overall, the conclusion I have come to is that the data that was presented doesn’t really support the fact that a HFM is a better pre-marathon meal to consume in order to perform better. If the data was more conclusive toward the HFM I may have been more convinced or persuaded by the study, but as they have presented the data I don’t agree.
The purpose of the paper was to investigate the effects of having a high carbohydrate and a high fat diet before a work out. The experiment was performed on eight male long distance runners that were in college. A week before the testing began the VO2max (maximum oxygen intake), when blood lactate begins to accumulate, and the lactic threshold, were all measured while the athletes ran on a treadmill; this was to determine what their pace should be during the experiment. The amount of lactic acid in the blood was determined from a blood sample taken from the ear lobe. The mass and ratio of body fat were also determined. The experiment began with the athletes eating 3 meals that were high in carbohydrates for three days and with a light workout, no longer than 30 minutes, on the first two days with no working out on the third day. Ten hours before the experiment the athletes went on a fast and four hours before the experiment they were randomly chosen to eat either a high carbohydrate meal (HCM) or a high fat meal (HFM). Three minutes preceding the experiment the athletes that ate a HFM ate either a placebo jelly or maltodextrin jelly and the athletes that ate a HCM ate the placebo jelly. Every athlete participated in all three trials; having a week break before starting the next trial. The experiment itself consisted of the athlete running on a treadmill for 80 minutes (at the pace that was determined during their initial testing the first week) until they reached exhaustion (they reached exhaustion because their glycogen levels were depleted not because there was too much lactic acid in their system). The results indicated that having HCMs three days before a race, eating a HFM a couple hours before the race, and having a small intake of a carbohydrate jelly, will increase the endurance of a long distance runner.
ReplyDeleteI agree that having a HCM a day before a race/game is beneficial in preparing for the “big day.” However, I do not agree with eating a HFM a couple hours before the race/game. When I played soccer, our coach always told us that you prepare for the game the days leading to the game. It does not matter (relatively speaking) what you eat/drink the day of. It might help the first couple minutes but it really depends what you put in your body the day(s) before.
I think the conclusion is overstated. The results do not take into account the history of the athletes being tested. It was mentioned that they were collegiate athletes, but what division did they compete in, how long have they been a runner, are they one of the top runners in their conference? For example, a runner who received first place in the NCAA Division I would be in better shape than a third string runner at a junior college. Therefore, the top runner might be able to handle a high fat meal and still be able to perform at a high level; whereas, the junior college runner would be affected by the high fat meal and produce different results obtained from the experiment. If I were setting up the experiment I would do different groups, each group accounting for different levels of expertise. One group would be marathon runners who have won medals in the Olympics, another group would be runners who compete in marathons worldwide and place top ten, the other groups would consist of top cross-country runners who are in college and in different divisions such as NCAA I, II, III, NCCAA I, II, III, NAIA I, II, III. Even if the experiment had to be performed at a lower scale, I would test cross-country runners who are in the same division (NAIA) but at different levels (I, II, III). Having this diverse of a test group would help validate that the results could pertain to the majority of long distance runners. The results also did not take into account that each participant had a week break in between testing. Some factors that are not considered are: were they healthy for all three trials, what did they do the week they were not testing, what did their diet consist of on their week off?
The study suggested that the intake of a HFM prior to exercise is more favorable for endurance performance than HCM. Also, HFM and maltodextrin ingestion following 3 days of carbohydrate loading enhances endurance running performance. However, there were a lot of factors that could have affected the results or given them different meanings. The main finding of this study was that carbohydrate ingestion subsequent to a meal that is high in fat after 3 days of glycogen loading can enhance the endurance running performance of athletes. Ingestion of a HFM lowers carbohydrate oxidation as compared with a HCM both at rest and during exercise. The HFM and carbohydrate ingestion (M) immediately before exercise improved the running time over the other two diets. The ingestion of carbohydrates 45 min before starting exercise significantly increased insulin concentrations during exercise and increased the use of glycogen. However, the authors believe that if carbohydrates are ingested immediately before exercise, the excessive secretion of insulin can be countered and suppressed by the insulin secretion inhibitory effects upon starting exercise.
ReplyDeleteAlso, high- to moderate-intensity exercises, such as time trials, were usually used in previous studies, but in this study, the subjects performed an exhaustion test, after a long duration run in order to induce lower glycogen level. Other possible considerations that could have affected the results include the differences in the nutritional status of the subjects prior to exercise, including the level of carbohydrate loading, and differences in the design of the exercise test. Additionally, the amount of carbohydrates taken in could have been a factor that influenced the results, along with the 10 hour fast the subjects went through prior to the study, the difference in protein percentage between the HCM and the HFM groups, and the fact that subjects in the HCM group only injected a placebo jelly, not the maltodextrin jelly. Maltodextrin effects may include rebound hypoglycemia. This occurs most often when maltodextrin is used as an exercise performance enhancer. In order to avoid a sudden decrease in blood sugar, it is important for those taking maltodextrin supplements to ingest the carbohydrates before the workout. To maintain blood sugar levels during the workout, carbohydrates should be taken at regular intervals during exercise.
Changing these minor shortcomings could vastly improve the validity of the article, but based on the hindrances present, I would have to disagree with the assumptions made in the paper. The subjects studied could also be a possible setback since they were all male athletes, which narrows down the possible outcomes. Also, the effects described were only short-term. Another in-depth study should be done in order to find out long-term effects of these types of diets, and they should also go more into detail about the negative effect of either a HFM or a HCM diet.
Other studies done on the effect of diets on endurance have found no clear effect on endurance performance – even though they had substantial effects on metabolism. It was observed that not all of the trials described the same effect.
References:
1. Effect of high-fat or high-carbohydrate diets on endurance exercise: a meta-analysis. http://www.ncbi.nlm.nih.gov/pubmed/15902985
2. Effect of High-Fat, High-Carbohydrate, and High-Protein Meals on Metabolism and Performance During Endurance Cycling. http://journals.humankinetics.com/ijsnem-back-issues/ijsnemVolume12Issue3September/EffectofHighFatHighCarbohydrateandHighProteinMealsonMetabolismandPerformanceDuringEnduranceCycling
3. What Are Maltodextrin Effects? http://www.wisegeek.com/what-are-maltodextrin-effects.htm
The article's main objective was to demonstrate the impact of a high carbohydrate or fat diet during prolonged strenuous exercise in eight 22 year old male athletes. Since muscle fatigue generally occurs when there is an accumulation of lactic acid, the lactic acid concentration was measured. There are three main pathways for regenerating ATP during muscle activity, direct phosphorylation of ADP by creatine phosphate, the anaerobic pathway, and the aerobic pathway. The results of the study focused on the aerobic pathway. When a concentration of 4mmol/L of lactic acid was reached, the rate was constantly increased about 10 miles per minute until the subject was exhausted. Oxygen deficiency occurs during prolonged strenuous exercise which was monitored measuring the maximum oxygen intake and using a twin-drum respirometer. The oxygen and carbon dioxide fractions were analyzed by mass spectroscopy then calibrated using standardized gas. The heart rates of each athlete was monitored at rest and for 30 seconds before the end of the exercise.
ReplyDeleteEach of the eight males consumed a rich carbohydrate meal three times a day for three days before the main trials. All of the males also participated in three trials that included a diet of high fat with maltodextrin, a rich fat meal with a placebo, and a high carbohydrate meal with a placebo. Maltodextrin is a carbohydrate that is absorbed faster than glucose.The athletes ate these meals four hours before running on a treadmill the unique marathon speed of each individual athlete. When the 4mmol/L of lactic acid was reached the load was increased at a continuous rate of 10 miles per minute until the athlete became fatigued. The total loading time was set to not exceed 80 minutes.The maltodextrin jelly and placebo was ingested three minutes before the trial. The three trials were separated by a week.
ReplyDeleteThe results of the experimented stated that the subjects that consumed the rich fat diet with the maltodextrin carbohydrate had a longer time until exhaustion. I agree with this part of the study because as exercise begins, muscle glyocgen provides most of the fuel. Then ATP is regenerated through the anaerobic pathway where glucose from the blood pyruvic acid from glycolysis and free fatty acids are the major sources of fuel. After about 30 minutes fatty acids become the major energy fuels. The maltodextrin would increase the blood glucose levels which which may increase the amount of ATP. The ingested fat meal would increase duration of prolonged exercise since it has been proven that oxidation of free fatty acids is the source of prolonged exercise. It seemed logical that an increase in the glycogen and free fatty acid concentration would increase the duration of prolonged exercise.
However, due to my research with Acetyl-CoA carboxylase I do not agree with the results of the comparison of high carbohydrate and high lipid consumption of this study. There should have been a difference between the time of exhaustion for subjects who ingested a high fat meal verses subjects who ingested a high-carbohydrate meal. Acetyl-CoA carboxylase is an enzyme that forms malonyl-CoA which is a great inhibitor of fatty acid oxidation. The activity of Acetyl-CoA would increase in a rich carbohydrate diet. (Medical Biochemistry, N.V.Bhagavan Fourth edition) Although glucose from the blood could be used as a form of fuel, it is shortly depleted after 30minutes.(Human Anatomy and Physiology 8th edition Elaine N. Marieb, Katja Hoehn) Free fatty acid becomes the major energy fuel source during endurance exercise, since there would be an increase in the malonyl-CoA in a high diet, there would not be enough free acid oxidation. Decrease in free acid oxidation would greatly decrease the duration of the athletes.
In contrast, a high intake of fat decreases the activity of acetyl-CoA carboxylase which decreases the levels of malonyl-CoA. This would allow more oxidation and an increase in the duration of the athletes.
Hence, this experiment had great intentions but had a set up that was over-simplified and over exaggerated. To begin, the subjects were all young males and lacked diversity in age. I would have liked to known how much of the maltodextrin was consumed. They did a great job measuring the levels of the blood glucose, insulin, free fatty acids, and lactic acid. I think they should get a more diversified subject group and redirect their attentions on the major energy sources in prolonged-duration exercise.
Many athletes follow the practice of carb loading. They eat a high carbohydrate meal the day before a game, race, or competition. For many years, it has been thought that carb loading increases the glycogen concentration in muscles, thus increasing endurance. Recent studies have implied that this may not be true. Eating a meal high in fat instead of a meal high in carbs may help conserve the body’s carb store and actually increase endurance. This paper studied the differences between a high carb meal (HCM) and a high fat meal (HFM) on distance running. The researchers tested eight long-distance runners to test the affects of a high fat meal versus a high fat meal. The study concluded that a high fat meal after three days of glycogen loading and an ingestion of carbohydrate jelly will improve endurance.
ReplyDeleteThis study was very interesting and provided a good beginning to determining whether or not carb loading is helpful or not. However, one of the main issues I had with the study was the small number of test subjects. Only eight people were tested. Also, all of the test subjects were males. In further testing, a larger group of people should be tested and both males and females should be included. I would be interested to see if there were any differences in results between males and females. It seems like the researchers tried to get a base line on all of the runner’s basic levels like height and weight, but I found it interesting that they did not include what the running results were without both the high fat meal and the high fat meal. The paper mentions that all of them were long-distance athletes, but it never records any results on how long they were able to run without a specific meal. I think it would be important to show those results, because they could be used to compare whether eating a high fat meal or a high fat meal improves endurance at all. Also, it would be interesting to see how this is affected by age. All of their subjects were around the age of twenty-two. The study concludes that three days of glycogen loading followed by a high fat meal and carbohydrate jelly improve endurance in running, but these results are overstated. Most of the times they show are very close for all of the diets. Several times throughout the paper, the writer’s state that the high fat meal works better than the high fat meal, but the results are so close with so few subjects that it is too early to say that with any certainty. Also because the study did not include the times each of these runners was able to run without a high fat meal or a high fat meal, you cannot really tell if the high fat meal or high fat meal actually helped at all. Another question I have is what would the affect of being outdoors have on these results? All of the conditions were so perfectly set to maintain testing conditions, but in true long-distance running and marathons, the conditions are not perfect. Would a higher altitude affect how these meals work? Also, how does sleep and rest affect a runner’s performance?
Hello, I log on to your blog like every week. Your humoristic style is witty,
ReplyDeletekeep up the good work!
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ReplyDeleteI am way out of my league on this one and everybody seem to have done a thorough job dissecting and coming up with the good and bad points of this article. Obviously, they really wanted the extra credit. However, I have time on my side. I agree most with Nadia that they should have diversified their subjects more. Of course favorable results will be achieved if all of your test subjects are young athletic males. How would it fair if it was a group of overweight menopausal women? Or young Asian gals?
This more recent study uses two groups (trained and untrained) men and measures their fat oxidation rates. I feel like this would be a more reasonable solution than an HFM and 3 days of carbo-loading. I am sure that better defined parameters on what an acceptable carbo loaded meal should be woud be helpful too. (I doubt Ling's Buffet or Dunkin Donuts would be as helpful as whole wheat pasta). http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3610290/
Eight male young adult athletes were given either a high fat meal with maltodextrin jelly or placebo jelly or a high carbohydrate meal with placebo jelly four hours before performing an exhaustion exercise test after three days of “carb loading”. The results indicated that a high fat meal with maltodextrin jelly is the best of the three meals for endurance. Additionally, athletes who ate high fat meals had longer endurance than those who ate high carbohydrate meals. It is not surprising that the athletes that ingested high fat meals had significantly higher resting and active fat oxidation rates and athletes that ingested high carbohydrate meals had significantly higher resting carbohydrate oxidation rates. It was surprising that the active carbohydrate oxidation rates were higher in athletes that ingested high fat meals with maltodextrin jelly than those who had high fats meals with the placebo jelly. Free fatty acid levels were also much higher during activity in the athletes who ingested a high fat meal. This indicates that the athletes who ingested a high fat meal were able to utilize energy stores more effectively.
ReplyDeleteOne strength of the study was the method of exercise chosen to measure endurance, fat oxidation rates and carbohydrate oxidation rates. The exercise was an exhaustion test instead of a time trial allowing it to more accurately measure endurance. Also, the length of the exhaustion test allowed the researchers to measure oxidation rates at more intervals. Another strength was that the athletes themselves believed that a high carbohydrate meal was preferable before exercise to ensure maximum endurance. However, the results showed that the opposite was true. This indicates that no psychological pre-disposition affected the results. Overall, the experiment was set up in a controlled manner that minimalized conditions that could skew the results. A major weakness of this article was the fact that there were only 8 test subjects. This experiment needs to be repeated with a much larger sample size to ensure statistical accuracy and significance.
I found this study to be very interesting. I have always been told to eat carbs before a run; it's odd to hear that this is not necessarily true. I thought that it was interesting that the group with the high fat meals before working out had the longest endurance. That is the opposite of what you would think.
ReplyDeleteThis is a very interesting study. It is common to think that a fat diet is more unhealthy than a carbs diet. This study was done in athletes. I wonder what would the results be if it was done in sedentary people. Most people don't exercise regularly and the effects of their diet is important to their overall health. This could help create an awareness of eating habits in regular people.
ReplyDeleteI found this article to be quite intriguing, however too much of anything is a bad thing. For instance, I was reading a journal article, titled Reduced neurotrophic factor level is the early event before the functional neuronal deficiency in high-fat diet induced obese mice.(1) Something that I was previously unaware of is that neurodegeneration can be a symptom of high fat diet induced obesity.(1) There has also been a multitude of research done examining the correlation between a high fat diet and dementia.(1) The researchers used a high fat diet obese mouse and compared it with a non dieting mouse, and found no obvious differences between the two.(1) Eventually the data showed that the neuronal change in the high fat diet mouse began due to neurotrophic factors.(1) The scientists believe that their results will aid in discovering a preventive strategy for neurodegeneration.(1) With that being said, a high fat diet can help with endurance and there are positive aspects to it. However, it all comes down to the person. Before anyone decides to drastically change their diet, it is always best to consult their physician, because what works for one person does not mean it will work for everyone.
ReplyDeleteReferences
1.Wang H, Yin H, Zhang G, et al. Reduced neurotrophic factor level is the early
event before the functional neuronal deficiency in high-fat diet induced
obese mice. Metabolic brain disease. September 2016. http://www.ncbi.nlm.nih.gov/pubmed/27624843. Accessed September 16, 2016.
I really enjoyed reading this article because I was able to relate to it. In high school, I was on the basketball team and ran track. Basketball, more so than track, required high performing endurance. I always had pregame jitters really bad, and so often, I would forget to eat. However, if my mom or mamaw was anywhere near me, they would force me to eat something. My mom was good to make me eat pasta or another high carb meal before playing in games. There was a definite difference in my performance when I did eat a high carb meal. In track, since it required short bursts of energy, I ate basically whatever I wanted as long as it was not very heavy. However, not being an athlete anymore and having my physical activity significantly reduce, I can't eat the same way that I did before. It is cool,though, that science was able to back up my mom and mamaw for always forcing me to eat before my games and meets.
ReplyDeleteAll things in moderation, that is, too much or too little of anything could be bad. I was always told what to eat before and after practices and games by my coaches in high school and here at SEU. There is definitely a major difference in my performance depending on what I eat and when I eat it.
ReplyDeleteThe idea that fat is better than carbs to allow physical endurance is rather surprising. I had gained the understanding that high-fat containing foods were detrimental to health overall, and athletes were to strictly limit their intake of it. Yet, according to this study, that may not be completely true. Contrarily, though, the study’s subject group was very specific – male college athletes. Therefore, the results do not represent valid outcomes in regards to women college athletes, elder athletes, etc. (although their discussion section refers to athletes in general).
ReplyDeleteThis article was interesting to me because I have always heard the phase "carbo-load". I would have never have thought that high fat containing foods were be beneficial at all. I have always heard that it is important to avoid these foods as much as possible. However, this study seems to say that it could have some benefits. Overall, I thought that the study was very educational and a good read!
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