Impact of intermittent vs. continuous energy restriction on weight and cardiometabolic factors: a 12-month follow-up.

Abstract

Intermittent energy restriction continues to gain popularity as a weight loss strategy; however, data assessing it's long-term viability is limited. The objective of this study was to follow up with participants 12 months after they had completed a 12-month dietary intervention trial involving continuous energy restriction and two forms of intermittent energy restriction; a week-on-week-off energy restriction and a 5:2 programme, assessing long-term changes on weight, body composition, blood lipids and glucose. 109 overweight and obese adults, aged 18-72 years, attended a 12-month follow-up after completing a 12-month dietary intervention involving three groups: continuous energy restriction (1000 kcal/day for women and 1200 kcal/day for men), week-on-week-off energy restriction (alternating between the same energy restriction as the continuous group for one week and one week of habitual diet), or 5:2 (500 kcal/day on modified fast days each week for women and 600 kcal/day for men). The primary outcome was weight change at 24 months from baseline, with secondary outcomes of change in body composition, blood lipids and glucose. For the 109 individuals who completed the 12-month follow-up (82 female, 15 male, mean BMI 33 kg/m2), weight decreased over time with no differences between week-on and week-off and continuous energy restriction or 5:2 and continuous energy restriction with -4.5 ± 4.9 kg for continuous energy restriction, -2.8 ± 6.5 kg for week-on, week-off and -3.5 ± 5.1 kg for 5:2. Total cholesterol reduced over time and glucose, HDL, LDL and triglycerides were unchanged. Intermittent energy restriction was as successful in achieving modest weight loss over a 24-month period as continuous energy restriction.