Role of Adaptive Thermogenesis in Unsuccessful Weight-Loss Intervention

Angelo Tremblay; Geneviève Major; Éric Doucet; Paul Trayhurn; Arne Astrup

Disclosures

Future Lipidology. 2007;2(6):651-658. 

In This Article

Adaptive Thermogenesis & Body Weight Instability

Body weight instability, which is also generally referred to as the 'yoyo phenomenon', seems to be the normal biological reaction to uncontrolled and quantitatively important negative energy balance. The weight regain that generally follows this large energy deficit may exceed weight loss so that a net weight gain may be the outcome of such a weight cycle. Approximately two decades ago, the yoyo effect was tested as a factor that could explain, per se, the proneness to a positive energy balance in animals.[60,61,62] Although this valuable testing demonstrated the potential to induce an increase in food efficiency and/or weight gain, subsequent human studies have not provided a clear support to this concept.[63,64,65] This may not be so surprising if one considers that clear demonstration of weight cycling on energy expenditure is practically untestable for ethical reasons. Indeed, it would be ethically unacceptable to submit individuals to one or several severe weight cycles when an investigator cannot exclude the possibility of a permanent handicap in the accuracy of energy-balance regulation as a consequence of the testing.

As previously reported,[59] we had the opportunity to complete two case studies in which we could test the effect of weight cycling on adaptive thermogenesis under well-standardized conditions. In the first study, an athletic male explorer was first tested in the Laval University respiratory chamber under well-standardized experimental conditions.[66] As shown in Figure 1, this measurement was followed by pre-expedition overfeeding that induced a 5 kg weight gain. After overfeeding, he engaged in a 22-day cross-country skiing expedition through Greenland that resulted in a weight loss of 8.5 kg. Figure 1 also shows that indirect calorimetry measurements were repeated after he had recovered his baseline morphological profile. It is also important to note that this post-expedition measurement was performed under conditions similar to baseline measurement for energy and macronutrient intake, as well as for spontaneous physical activity in the chamber. Despite this optimal standardization for factors influencing 'obligatory thermogenesis', daily energy expenditure was reduced by 1.4 MJ (approximately 350 kcal) following the expedition.

Figure 1.

Variations in body weight and daily energy expenditure in response to a weight cycle imposed by an expedition in Greenland (Subject 1) and in Antarctica (Subject 2).

A comparable result was obtained in the second study, which involved the testing of another male explorer who was also subjected to whole-body indirect calorimetry measurements before and after a 65-day expedition in Antarctica. As expected, the expedition induced a considerable body weight loss (13.2 kg) that had to be recovered following the expedition before a second series of measurements could be performed in the respiratory chamber. Thus, as for case study 1, this subject was tested at the same body weight and composition status before and after the expedition as well as under standardized nutritional and activity conditions in the chamber. Figure 1 shows that the weight loss/regain cycle again resulted in a marked decrease (1.0 MJ/day) in daily energy expenditure, which provides further evidence of the impact of weight cycling on adaptive thermogenesis.

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