Table 1

 Summary of evidence for various dietary approaches in the management of overweight and obesity

Dietary approachEvidence of effectivenessInconclusive/inadequate evidence
VLCD, very low calorie diet; LCD, low calorie diet; CHD, coronary heart disease, RCT, randomised controlled trial, GI, glycaemic index.
Low fatSpontaneous weight loss19–21Unclear if energy restriction + fat restriction more effective than fat restriction alone22
Risk reduction21
Maintenance of modest weight loss with low fat diet as part of comprehensive treatment programme23
Fixed energy deficitModest weight loss25Some evidence of improved compliance relative to more severe energy restrictions25
Meal replacementsWeight loss and maintenance27Unclear of outcome if product not free
Unclear of effectiveness in morbidly obese
VLCDsShort term weight loss greater than LCD22Relative effectiveness of VLCD versus LCD over the long term (>1 year)22
Low glycaemic indexRisk reduction for CHD and type 2 diabetes30No RCT of low GI diet on weight loss over time29
High protein low carbohydrateShort term and long term safety profile unclear31
Effectiveness on long term weight loss and maintenance not available