Increasing energy flux to decrease the biological drive toward weight regain after weight loss - A proof-of-concept pilot study.
OBJECTIVE
Weight loss induces compensatory biological adjustments that increase hunger and decrease resting metabolic rate (RMR), which increase propensity for weight regain. In non-obese adults high levels of physical activity coupled with high energy intake (high energy flux) are associated with higher RMR and reduced hunger. We tested the possibility that a high flux state attenuates the increase in hunger and the decrease in RMR characteristic of diet-induced weight loss.


METHODS
Six obese adults [age (mean ± SE) = 42 ± 12 y; body mass index (BMI) = 35.7 ± 3.7 kg/m2] underwent measures of RMR, the thermic effect of a meal (TEM), and fasting and postprandial measures of hunger and fullness as well as plasma glucose and insulin. Following weight loss, subjects completed two 5-day conditions of energy balance in random order-Low Flux (LF): sedentary with energy intake (EI) = RMR (kcal/d) × 1.35; and High Flux (HF): net exercise energy cost of ∼500 kcal/d and EI = RMR (kcal/d) × 1.7. RMR was measured daily for each flux condition. The morning following each of the respective experimentally controlled HF and LF conditions (flux day 5), they underwent the same pre-weight loss tests and also reported their perceptions of hunger and fullness during the previous four days of HF and LF, respectively.


RESULTS
Average daily RMR was higher during HF (1926 ± 138 kcal/day) compared to LF (1847 ± 126 kcal/day; P < 0.05). Perceived hunger at the end of day was lower (p < 0.03) and fullness throughout the day was higher (p < 0.02) in HF compared to LF conditions. On day 5 of each flux condition, the thermic effect of a meal and circulating glucose and insulin after the meal did not differ between HF and LF.


CONCLUSION
Following weight loss, compared to a sedentary LF state of energy balance, a short-term HF energy balance state is associated with higher RMR, lower perceived hunger, and greater perceived fullness, all of which could help attenuate the biologic drive to regain weight. Given the pilot nature of this study and the relatively short period of time spent in the high and low flux states, future research is needed to address this research question in a larger sample over a longer time period.
['Paris|Hunter L|HL|', 'Foright|Rebecca M|RM|', 'Werth|Kelsey A|KA|', 'Larson|Lauren C|LC|', 'Beals|Joseph W|JW|', 'Cox-York|Kimberly|K|', 'Bell|Christopher|C|', 'Melby|Christopher L|CL|']
D000328:Adult D001069:Appetite Regulation D015992:Body Mass Index D000068959:Body Weight Maintenance D004038:Diet, Reducing D002149:Energy Intake D004734:Energy Metabolism D015444:Exercise D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D008954:Models, Biological D009765:Obesity D010349:Patient Compliance D010865:Pilot Projects D000075082:Proof of Concept Study D055502:Secondary Prevention D015430:Weight Gain D015431:Weight Loss
Weight regain Weight loss Hunger Metabolism Obesity Exercise