Role of Nonexercise Activity Thermogenesis in Resistance to Fat Gain in Humans

Abstract

Humans show considerable interindividual variation in susceptibility to weight gain in response to overeating. The physiological basis of this variation was investigated by measuring changes in energy storage and expenditure in 16 nonobese volunteers who were fed 1000 kilocalories per day in excess of weight-maintenance requirements for 8 weeks. Two-thirds of the increases in total daily energy expenditure was due to increased nonexercise activity thermogenesis (NEAT), which is associated with fidgeting, maintenance of posture, and other physical activities of daily life. Changes in NEAT accounted for the 10-fold differences in fat storage that occurred and directly predicted resistance to fat gain with overfeeding (correlation coefficient = 0.77, probability < 0.001). These results suggest that as humans overeat, activation of NEAT dissipates excess energy to preserve leanness and that failure to activate NEAT may result in ready fat gain.

Within- and between-individual variability in estimated energy expenditure and habitual physical activity among young adults

“…Schoeller's overview emphasizes the relatively low amount of daily variation occurring in TEE and also the body's tendency to increase energy stores as the result of overfeeding. Levine et al (1999) emphasized the possibility of increased amounts of nonexercise activity thermogenesis (NEAT) to resist fat gain accompanied with overfeeding; however, it now appears that levels of NEAT are static within an individual, regardless of fat gain (Levine et al, 2005). To date, the effects of increased daily PA on TEE have produced conflicting results.…”

Effects of intrinsic aerobic capacity, aging and voluntary running on skeletal muscle sirtuins and heat shock proteins

“…Thermogenesis is an energy demanding process that has a significant contribution to daily 66 total energy expenditure (TEE), body weight and health (Levine, Eberhardt & Jensen 1999, 67 Rosenbaum et al 2008). High thermogenesis is linked to high physical activity (PA) level, as 68 body temperature rises as a result of increased muscular activity (Gleeson 1998).…”

Oxyntomodulin increases energy expenditure in addition to decreasing energy intake in overweight and obese humans: a randomised controlled trial

“…15 It has been reported that low physical activity accounted for 77% of weight gain over a year in one prospective study 16 and inactivity is a major determinant of increased adiposity during overfeeding. 17 Indeed, the variability of response to an obesigenic environment may be explained by inter-individual differences in non-exercise physical activity, which vary over 30-fold. 3 An anti-obesity treatment which both increases activity and reduces energy intake is more likely to be a successful longterm therapy for obesity.…”