Summary of evidence for various dietary approaches in the management of overweight and obesity
| Dietary approach | Evidence of effectiveness | Inconclusive/inadequate evidence |
|---|---|---|
| VLCD, very low calorie diet; LCD, low calorie diet; CHD, coronary heart disease, RCT, randomised controlled trial, GI, glycaemic index. | ||
| Low fat | Spontaneous weight loss19–21 | Unclear 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 deficit | Modest weight loss25 | Some evidence of improved compliance relative to more severe energy restrictions25 |
| Meal replacements | Weight loss and maintenance27 | Unclear of outcome if product not free |
| Unclear of effectiveness in morbidly obese | ||
| VLCDs | Short term weight loss greater than LCD22 | Relative effectiveness of VLCD versus LCD over the long term (>1 year)22 |
| Low glycaemic index | Risk reduction for CHD and type 2 diabetes30 | No RCT of low GI diet on weight loss over time29 |
| High protein low carbohydrate | Short term and long term safety profile unclear31 | |
| Effectiveness on long term weight loss and maintenance not available | ||