Effects of prescribing 1,000 versus 1,500 kilocalories per day in the behavioral treatment of obesity: A randomized trial

Objective Controversy exists regarding the optimal energy prescription to promote successful long‐term behavioral management of obesity. Prescribing intake of 1,000 (vs. 1,500) kcal/day may produce larger initial weight reduction, but long‐term advantage remains unclear. The effects of prescribing 1,000 versus 1,500 kcal/day on 6‐ and 12‐month weight changes within behavioral treatment of obesity were examined. Design and Methods Participants were 125 obese women (mean ± SD; BMI = 37.84 ± 3.94 kg/m 2 ) randomly assigned goals of 1,000 or 1,500 kcal/day. Results From months 0 to 6, participants prescribed 1,000 kcal/day lost more weight than those prescribed 1,500 kcal/day (mean ± SE = −10.03 ± 0.92g vs. −6.23 ± 0.94 kg, P = 0.045); however, from months 7 through 12, only the 1,000 kcal/day condition experienced a significant weight regain (1.51 ± 0.77 kg, P = 0.025). Baseline caloric consumption moderated the effect of treatment on regain; participants with baseline intakes ≧2,000 kcal/day who were assigned 1,000 kcal/day were significantly more susceptible to weight regain than those assigned 1,500 kcal/day ( P = 0.049). At month 12, a significantly greater percentage of 1,000 kcal/day participants achieved weight reductions of 5% or more than those prescribed 1,500 kcal/day. Conclusion Encouraging obese individuals in behavioral treatment to adhere to a 1,000 kcal/day intake may increase their likelihood of achieving clinically meaningful weight losses.