Last update and review: December 21, 2020.
A short summary.
Moro et al., 2020 (1), set out to test time-restricted eating in a group of young elite cyclists. However, their study is full of errors and confusion. We do not learn much. The rare intersting result is that the young cyclists could handle 700 grams a day of carbohydrates, in the context of a total caloric intake of 4800 kCal, without an increase in insulin and triglycerides.
The study by More et al., 2020 (1), is another illustration of the fact that, in certain conditions, a very high carbohydrate intake can be well-tolerated and does not damage metabolism immediately.
It is, however, not clear what impact such diet may have on metabolism at a longer term.
Diet and blood markers of elite under-23 years old cyclists.
The subjects.
Moro et al., 2020 (1):
Sixteen elite under-23 cyclists were randomly assigned either to a time restricted eating (TRE) group or a control group (ND). The TRE group consumed 100% of its estimated daily energy needs in an 8-h time window (from 10:00 a.m. to 6:00 p.m.).
Training.
Moro et al., 2020 (1):
The study was conducted during the winter precompetition season. As such, most of the training consisted of long outings at a mild/medium pace at the steady state. The training schedule included 500 ± 50 km/week divided into 6 sessions per week that took place within the feeding time window (10 a.m.-6 p.m.).
The experiment lasted about one month.
The daily intake of carbohydrate was 700 grams a day(!) and the total caloric intake was 4800 kCal.
The researchers put the young athletes on a 4800 kCal a day diet. The daily intake of carbohydrate was 700 grams a day(!). How much the athletes were eating at baseline is not clear. However, since the athletes remained weight-stable, we may presume that the caloric intake was similar before the experiment.
The study by Moro et al., 2020 (1), is full of errors and confusion.
The study by Moro et al., 2020 (1), is full of errors and confusion. For example, we have no idea with what assay free testosterone was measured and what the reference ranges for that assay are. Total testosterone was not measured at all, despite the fact that total testosterone is a more reliable laboratory test. According to the table 4 reproduced below, IGF-1 increased, which is the opposite direction from what is expected in training and time-restricted eating subjects. Were the subjects eating less before the experiment? Who knows. We, therefore, can’t really trust the authors, nor can we learn that much. Most of the text and the authors’ conclusions should be ignored.
Fasting triglycerides and insulin are normal in both groups of young elite athletes.
However, if we assume that at least some of the blood markers are reported correctly, we can see that fasting triglycerides and insulin are normal in both groups of young elite athletes.
CRP of 0.08 mg/dL may indeed be the optimum.
It is also interesting to note that after 24-hour period without training, C-reactive protein (CRP) in these young athletes is down to 0.08 mg/dL. Some proposed that the normal CRP level is 0.08 mg/dL. If we can trust this particular piece of data from this study by Moro et al., 2020 (2), we have an element that confirms that CRP of 0.08 mg/dL may be the optimum.
IGF-1 results: a contradiction between the text and the table data.
As we kept exploring the article, we realized that Moro et al., 2020 (1), have probably reversed that data on IGF-1 in their table 4. Indeed, the value from “before” the experiment (291.60ng/mL) was reversed with the value measured after the experiment (244ng/mL).
An example of the typical chaos in the published literature and of physiological illiteracy of the PhD crowd.
The error with IGF-1 is an example of the typical chaos in the published literature. Sloppy editing is one thing. But Moro et al., 2020, do not understand physiology well. Indeed, the lower IGF-1 value is probably explained by the longer time since the last meal.
Elite athletes can develop metabolic syndrome and diabetes.
Beware, however, that even young elite endurance athletes occasionally develop metabolic syndrome and even type 2 diabetes. Tim Noakes, a physiology professor and an ardent advocate of low carb ketogenic diets, is one example of that.
Tim Noakes on a social network:
…(my) fasting insulin (was) 5-8 times normal when I was 29 running 120km/week and (my) BMI (was) 20-21kg/m2.
Conclusions.
It is amazing how much carbohydrates this group of young athletes can absorb without any apparent damage to their metabolism. It is, however, not clear what the result of such high intakes may be at a longer term.
Also, it is reasonable to select a physical activity that does not require extreme intakes of carbohydrate or food in general.
Different sports are often poorly designed from the physiological point of view. Endurance sports are great but need to be practiced intelligently.
Self-monitoring is an immediate actionable item that athletes are advised to do.
Published “peer-reviewed” literature is full of errors, is not really peer-reviewed, and the authors may have serious gaps in their understanding of physiology.
It is important to understand and to always remember what the published peer-reviewed literature really is. It is important to remain critical. Correct terminology in describing the outside world is also important. Thus, using the misleading terms such as “Science”, understood by many as “Absolute Unquestionable Truth”, “experts“, “scientists” may become a form of self-brainwashing. Relying more on one’s own Common Sense, Logic, Pattern Recognition, that is, personal qualities that do exist and can be improved over time, is a better way to navigate the outside world.
Related:
Selected references:
1. Moro T, Tinsley G, Longo G, et al. Time-restricted eating effects on performance, immune function, and body composition in elite cyclists: a randomized controlled trial. J Int Soc Sports Nutr. 2020;17(1):65.
3 Comments