Approximately 90% of weight-reduced individuals eventually return to their previous body weights. This is largely attributed to adaptive thermogenesis, the changes in metabolic processes that occur as a result of weight loss. Adaptive thermogenesis creates an ideal physiological environment for weight regain by causing energy expenditure to decrease beyond what is predicted from changes in body composition. Therefore, identifying factors that counteract adaptive thermogenesis is important for long-term weight loss and maintenance. Several factors have been shown to influence adaptive thermogenesis, but until recently the impact of high protein intake has remained unclear. A new study published in The Journal of Nutrition investigated the effects of a controlled high protein diet compared with a moderate protein diet on components of energy expenditure, energy balance and adaptive thermogenesis. Researcher Mathijs Drummen (Maastricht University) and colleagues hypothesized that a controlled high protein diet would counteract adaptive thermogenesis and increase energy expenditure.
The PREVIEW study, which included 2326 adults, consisted of a 3-y weight loss and weight maintenance intervention that emphasized diets differing in the protein/carbohydrate ratio. The study consisted of 2 phases: an 8-wk weight-loss period consuming either a high-protein diet or a moderate-protein diet, followed by a 34-mo weight maintenance period. Nearing the end of the weight maintenance period, 38 representative study participants stayed in a respiration chamber for 48 h where energy expenditure and respiratory quotient were assessed. Predicted resting energy expenditure was calculated based on fat-free mass and fat mass. Adaptive thermogenesis was assessed by subtracting measured resting energy expenditure from predicted resting energy expenditure.
Measurements of energy expenditure showed that a 48-h higher protein diet compared with a medium protein diet induced a negative energy balance and increased resting energy expenditure. The high protein diet was also able to counteract adaptive thermogenesis during weight maintenance after weight loss, whereas the medium protein diet was not. In addition, adaptive thermogenesis was positively associated with a positive energy balance, which indicates its potential for weight regain after weight loss. Study results provide evidence that increased protein/carbohydrate ratio may help counteract adaptive thermogenesis and therefore may be helpful for long-term weight maintenance after weight loss. A corresponding editorial by Stuart Phillips (McMaster University) commends this study for adding important mechanistic evidence to better understand weight maintenance after weight loss with the consumption of a higher-protein diet. “This elegant and provocative study from the PREVIEW trial shows that the balance of energy coming from protein at the expense of carbohydrate opposed adaptive thermogenesis by small but significant margins.”
Reference Drummen M, Tischmann L, Gatta-Cherifi B, Fogelholm M, Raben A, Adam TC, Westerterp-Plantenga MS. High Compared with Moderate Protein Intake Reduces Adaptive Thermogenesis and Induces a Negative Energy Balance during Long-term Weight-Loss Maintenance in Participants with Prediabetes in the Postobese State: A PREVIEW Study. J Nutr 2019 Nov 22 (Epub ahead of print; DOI: https://doi.org/10.1093/jn/nxz281).
Images credit: canva.com