Oct 09, 2020


Author: Prof. Diego A. Bonilla, ISAK 3

Lecturer-Researcher | Research Division, DBSS International
Researcher at BioMol (UD), GICAFS (Unicordoba) & kDNA Genomics (UPV)
Science Product Manager at MTX CORPORATION (Europe)

ResearchGate | Scopus | Web of Science ResearcherID 

Over the summer season, the goal of many people will be to have a low body fat percentage and a respectable amount of lean mass. However, the incalculable amount of misinformation, the unsuccessful advice or the lack of adherence to the proposed programs increase the possibility of using ineffective products or prohibited/dangerous substances as long as you lose a few pounds.

In order to provide recommendations and design strategies to improve body composition, it is necessary to understand the relevance of the body adaptation processes. Perhaps you have heard the word adaptation in an academic text, in a NatGeo documentary or in any other situation where something fits what is out of the ordinary. For our body, like any other system in nature, the adaptation is a result of a stimulus-response process. That is, our body responds to certain external stimuli (whether a physical training program, a type of diet, an injury, etc.) and generates a physiological response (for example, after a meal insulin is released from the pancreatic beta cells to help regulate blood glucose levels, or after a few minutes on the treadmill adrenaline is released after activation of the hypothalamic-pituitary-adrenal axis to help regulate the production of energy needed for movement). In case the stimulus is repetitive, our system will adapt by producing the necessary modifications. 

This is how changes in body composition are generated. A person who has been consuming for some time more calories (energy surplus) than he/she normally spends (including or not a low level of physical activity) will generate an accumulation of fat in his/her adipose tissue, which is nothing more than an adaptive response (Figure 1). Notwithstanding, these adaptation processes will take as long as the changes to occur at the metabolic-genetic, cellular and tissue levels (Müller et al. 2016). 

Figure 1. The changes in body composition are nothing more than adaptations to stimuli that come mainly from energy intake and the physical activity level.

So, to think that this phenomenon of adaptation (I mean those extra kilos) can be solved in a very short time with a few doses of some "magic product" is a complete mistake. And even more, to think that it is not necessary to make any kind of physical effort to get sustained results over time is totally wrong. Today we know the advantages of a controlled intake of calories (basically a caloric deficit, if the objective is to reduce the percentage of fat), a strength training program combined with cardiovascular exercise and an adequate protein overfeeding to improve body composition.

We must bear in mind that there is no unique path to achieve this fat reduction, as it has been shown that any type of diet (e.g., ketogenic diet, intermittent fasting, Mediterranean diet, etc.) is effective as long as it generates a caloric deficit (consuming fewer calories than we spend daily) (Aragon et al. 2017). However, the dietary component is not the only thing that needs to be adjusted, as it is well known that caloric restriction programs can reduce the amount of muscle mass. That is why we find the practice of strength exercises and having a high-protein diet (Ramage et al. 2014) among the strategies to prevent this undesirable effect. This not only promotes the maintenance/development of muscle mass, but also has interesting metabolic advantages and generates more adherence to weight loss programs. We cannot conclude this entry without mentioning the advantages of performing "refeeds" (Campbell et al. 2020) and "diet breaks" (Escalante et al. 2020) throughout the process, since they have been reported to optimize the reduction of body fat, contribute to the preservation of muscle mass, prevent significant reductions in resting energy expenditure, and also favor adherence to the program. Finally, you might ask yourself, what about the "fat burners"? Well, these types of dietary supplements do not work on their own because, as mentioned above, fat reduction is an adaptive, time-consuming process that depends on the relationship between energy intake and energy expenditure. Furthermore, not all products on the market optimize the reduction of body fat percentage during a well-structured weight loss program (i.e. caloric deficit, with strength training and high-protein diet), as many abuse marketing, are not scientifically supported or simply do not generate clinically relevant results. Among some interesting options that have been evaluated in different populations are caffeine and green tea extract (EGCG 50%) (Katada et al. 2020), Ashwagandha (Withania somnifera) in subjects with chronic stress (Choudhary et al. 2017) and some foods with thermogenic potential such as chili (capsaicinoids) (Urbina et al. 2017), pepper and ginger (Taghizadeh et al. 2017). If you want to go deeper into thermogenesis, we published recently a review on the new advances in thermogenesis to obesity diagnosis, development and treatment from a nutrition and physical activity insight, as well as we reported the first experimental results of the pathogenic polymorphism C427T (rs104894319) in the UCP3 gene in Venezuelan population (Bonilla et al. 2018). Remember: "fat burners" are not effective per se, but they can promote exercise adaptation, increase energy expenditure at rest or increase adherence to the weight loss program.

Practical recommendations for professionals: 

  1. Calculate the individual's total daily energy expenditure and establish the caloric deficit. You can be guided by estimation equations or devices to calculate the daily energy expenditure according to the heart rate (POLAR, GARMIN, etc.); however, please note that in practice there is no exact method to calculate this value, so it is recommended to perform a dietary intake and body mass registration for two weeks before starting the program in order to calculate the maintenance calories. Moreover, consider that the caloric deficit is individual and will depend on the body composition and training experience (specifically on the physiological adaptations to the physical effort) of the client.
  2. Calculate caloric intake from protein. While the high-protein diet is important, it is not necessary to abuse and exaggerate protein intake. Keep in mind that the daily requirement during a fat reduction program will depend on the individual's age, current body composition, and physical activity level. For instance, a man between 30-40 years old during a weight loss program (energy deficit) would need among 2.4-2.8 g PRO per kilogram of fat-free mass per day.
  3. Calculate the distribution of carbohydrates and lipids according to the individual's preference until the energy target is reached. Adherence comes first! Regardless of whether you as a professional follow a ketogenic diet, love intermittent fasting or are faithful to the Paleolithic diet, please respect the likes of the subject and distribute carbohydrates and lipids accordingly (obviously within the framework of objective nutritional education). This will facilitate adherence to the nutritional program. Keep in mind that nutritional education is not about telling the subject to follow a diet, but about teaching him the proper healthy energy distributions or proportions to reach the goal. This is not about restrictions or letting him/her eat poor quality or energy-dense foods, but adjusting the macros/energy so that the change is not drastic from the beginning and explain the intermittent and fluctuant fashion of the program (Figure 2).
Figure 2. Realistic behavior of body mass during an optimal weight loss program. Nutritional education and adherence to diet is the key to optimize changes in lifestyle, which at the end will result in an adaptation scenario (better body composition).


Disclaimer: This text does not represent the last or only truth about this topic; in fact, further research is needed to have a better comprehension of this phenomenon. However, a contextualized approach about each individual under professional follow-up based on the trial/error will have more possibilities of adherence, success and fewer health risks, if compared to reductionism and pseudoscience strategies promoted by marketing inter alia.





1. Aragon, A.A., Schoenfeld, B.J., Wildman, R. et al. International society of sports nutrition position stand: diets and body composition. J Int Soc Sports Nutr 14, 16 (2017). 

2. Bonilla, D. A., Marín, E., Pérez, A., Carbone, L., Kammerer, M., Vargas, S., ... & Petro, J. (2018). Thermogenesis and Obesity; A Brief Review and rs104894319 Polymorphism in Venezuelan Population. EC Nutrition, 13(1), 4-16.

3. Campbell, B. I., Aguilar, D., Colenso-Semple, L. M., Hartke, K., Fleming, A. R., Fox, C. D., ... & Ford, S. (2020). Intermittent Energy Restriction Attenuates the Loss of Fat Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial. Journal of Functional Morphology and Kinesiology5(1), 19.

4. Choudhary D, Bhattacharyya S, Joshi K. Body Weight Management in Adults Under Chronic Stress Through Treatment With Ashwagandha Root Extract: A Double-Blind, Randomized, Placebo-Controlled Trial. J Evid Based Complementary Altern Med. 2017;22(1):96-106. doi:10.1177/2156587216641830

5. Escalante, G., Campbell, B. I., & Norton, L. (2020). Effectiveness of Diet Refeeds and Diet Breaks as a Precontest Strategy. Strength & Conditioning Journal.

6. Katada, S., Yanagimoto, A., Matsui, Y. et al. Effect of tea catechins with caffeine on energy expenditure in middle-aged men and women: a randomized, double-blind, placebo-controlled, crossover trial. Eur J Nutr 59, 1163–1170 (2020). 

7. Müller MJ, Enderle J, Bosy-Westphal A. Changes in Energy Expenditure with Weight Gain and Weight Loss in Humans. Curr Obes Rep. 2016;5(4):413-423.

8. Ramage S, Farmer A, Eccles KA, McCargar L. Healthy strategies for successful weight loss and weight maintenance: a systematic review. Appl Physiol Nutr Metab. 2014;39(1):1-20. 

9. Taghizadeh, M., Farzin, N., Taheri, S., Mahlouji, M., Akbari, H., Karamali, F., & Asemi, Z. (2017). The effect of dietary supplements containing green tea, capsaicin and ginger extracts on weight loss and metabolic profiles in overweight women: A randomized double-blind placebo-controlled clinical trial. Annals of Nutrition and Metabolism70(4), 277-285.

10. Urbina, S. L., Roberts, M. D., Kephart, W. C., Villa, K. B., Santos, E. N., Olivencia, A. M., ... & Jäger, R. (2017). Effects of twelve weeks of capsaicinoid supplementation on body composition, appetite and self-reported caloric intake in overweight individuals. Appetite113, 264-273.


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