Intermittent energy restriction shows promise for weight loss
MedWire News: Intermittent energy restriction is an effective strategy for weight loss, and may offer additional metabolic benefits over continuous energy restriction, say UK researchers.
Weight-loss programs traditionally use continuous energy restriction but are hampered by poor compliance, which can attenuate many of the benefits of weight loss. A potential alternative strategy is intermittent energy restriction, in which short spells of severe restriction are alternated with longer periods of habitual energy intake.
"For some subjects, such an approach may be easier to follow and may overcome adaptation to the weight-reduced state by repeated rapid improvements in metabolic control," explain Michelle Harvie (University Hospital of South Manchester) and team.
To investigate, they recruited 107 overweight or obese women and randomly assigned them to follow a 6-month program of intermittent or continuous energy restriction. The former entailed restricting intake to 2710 kJ/day for 2 days each week while the latter restricted intake to 6276 kJ/day every day.
Women in both groups showed a significant reduction in body weight at 6 months, report Harvie et al in the International Journal of Obesity. Mean weight fell from 81.5 to 75.8 kg in the intermittent group and from 84.4 to 79.9 kg in the continuous group.
Women in both groups also showed significant but comparable reductions in body fat, fat-free mass, and waist/bust/hip/thigh circumferences.
The improvements in anthropometric parameters were accompanied by beneficial changes in serum markers including leptin, high-sensitivity C-reactive protein, total and low-density lipoprotein cholesterol, triglycerides, and blood pressure.
Both groups also experienced reductions in fasting insulin and insulin resistance, but the magnitude of reduction was significantly greater with intermittent than with continuous energy restriction.
Finally, adherence to the diet was good in both groups: 64% of the intermittent group and 55% of the continuous group achieved more than 5% weight loss. This may reflect the high motivation levels among participants and ongoing monitoring and motivational phone calls provided as part of the trial, say the authors.
"Our data suggest that periods of severe restriction may have different effects, which may be important in the long term for disease prevention," they conclude.
"Intermittent energy restriction can be offered as an alternative to continuous energy restriction for reducing obesity and obesity-related disorders in some individuals.
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By Joanna Lyford