Does exercise affect fat mass differently than a caloric deficit?

The increased risks associated with excess fat mass have been well established in the literature, and body fat appears^[1] to constitute a better metric than body mass index for determining cardiometabolic risk. Both the amount and distribution of body fat are important factors. As shown in Figure 1, visceral adipose tissue (VAT) appears^[2] to be more metabolically damaging than subcutaneous adipose tissue (SAT). As their names imply, they are anatomically different, but they also display distinct metabolic properties. An increase in VAT is more strongly associated^[3] with metabolic disease, and hence, it constitutes a particularly valuable target for reducing cardiometabolic risk.

Figure 1: Visceral vs. subcutaneous adipose tissue

Reference: Després et al. J Am Coll Cardiol. 2021 Aug. ^[4]

A negative energy balance is required to reduce fat mass, but it is theoretically possible that different ways of creating this negative balance reduce VAT and SAT differently. Therefore, the authors of this systematic review analyzed intervention studies that compared the effect of a negative energy balance induced by calorie restriction, exercise or both combined on relative loss of SAT versus VAT.

A higher body fat mass has been associated with increased metabolic risk, with visceral adipose tissue being of particular concern. It is currently unknown whether caloric deficits involving dieting, as opposed to exercise, can influence the relative loss of subcutaneous versus visceral adipose tissue. The aim of this study was to explore this question.