Research
Energy balance
Very-low-calorie diets (VLCDs) produce larger initial weight losses than conventional low-calorie diets but do not improve long-term weight maintenance outcomes.
Crash diets (600-800 calories) will help you lose weight faster initially, but you will likely regain it faster and end up at the same weight as if you had lost it slowly. For long-term success, avoid extreme restriction and focus on sustainable habits.
GoodRefutesHIGH confidence
VLCDs, however, have not been markedly successful in improving long-term weight loss outcomes. That is, larger weight losses induced by more severe calorie restriction are followed by larger and somewhat more rapid regains so that net effects 2 or more years after treatment are no better than with more traditional approaches.
Why this rating
Based on a specific study (Wadden et al., 1989) comparing VLCD vs. LCD over 5 years.
Source
Long-term maintenance of weight loss: Current status.
Robert W. Jeffery et al. · Health Psychology · 2000
DOI 10.1037/0278-6133.19.suppl1.5
narrative_reviewCited 1,104×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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