Maintaining It after Losing It: Advantage Protein!
Stuart M Phillips The Journal of Nutrition, 25 December 2019
The recidivism of weight loss during an energy deficit is substantial and there are a variety of theories as to why this is the case (1). One consistent finding, however, is that there are seemingly inevitable thermogenic processes that work to oppose weight loss (adaptive thermogenesis—AT) and likely contribute to weight regain (2). These processes, although seemingly “protective” in times of food scarcity, now work against weight loss in times of easy availability of highly processed, energy-dense, nutrient-poor, and palatable foods. Thus, there is a tremendous effort to ascertain what strategies could counter the weight loss–induced changes in AT that accompany weight loss in an effort to slow weight regain. If successful, such strategies would be of tremendous benefit and particularly in persons with type 2 diabetes for whom weight loss results in benefits both from a glycemic regulation standpoint and for general metabolic health (3). A number of strategies have been attempted to reduce AT including exercise, cold-exposure, and various compounds (drugs and nutraceuticals) designed to stimulate energy expenditure. The consumption of higher than recommended quantities of protein during and after weight loss has also been a topic of interest (4, 5) because higher dietary protein would support maintenance of fat-free mass, resulting in higher diet-induced energy expenditure and resting energy expenditure (REE) (6).
In this issue of The Journal of Nutrition, Drummen et al. (7) present an elegant and provocative study from the PREVIEW trial (8), showing that dietary macronutrient balance in post–weight loss prediabetics (34 mo after initial weight loss) is highly relevant. Specifically, the balance of energy coming from protein at the expense of carbohydrate opposed AT by small but significant margins. Specifically, with 25% compared with 15% of total dietary energy (at the expense of carbohydrate) coming from protein, participants exhibited negative energy balance (EB), a lower respiratory quotient (RQ), as well as a higher REE. Of note, EB was related to AT and RQ. Although it may seem that these differences are small, it needs to be appreciated that tipping the EB scales to favor maintenance of weight loss is a monumental task (1). Thus, use of multiple strategies to try to counter the weight loss–induced AT including activity- and diet-based changes would seem prudent. Increasing dietary protein consumption is clearly a manageable and feasible dietary strategy and, as Drummen et al. (7) clearly demonstrate, it is one that opposes weight loss–induced AT. Interestingly, the decades-old and often-stated reasons for opposition to higher-protein diets, namely bone loss (9) and compromised renal health (10), lack robust experimental evidence and thus are unfounded grounds on which to oppose a higher-protein diet, particularly after weight loss. Thus, one is forced to wonder why when obesity and type 2 diabetes are such problems, and weight loss is a “straightforward” solution, a higher-protein diet is not recommended more often to preserve weight loss? Accolades are due to Drummen et al. (7) for adding important mechanistic evidence to our evidence-based knowledge of better weight maintenance after weight loss with consumption of a higher-protein diet (5).
