This post is slightly controversial, but there is plenty of evidence to suggest that low calorie diets do not work (for the majority of people).
In the early 90’s the Women’s Health Initiative commissioned by the National Institute of Health set out to investigate a few critical issues with women’s health, namely do low fat diets help reduce the risk of heart disease and cancer.
One of the largest studies of our time with 50,000 women in a trial who were all instructed to take part in a low fat diet rich in fruit, vegetables and fibre. They were all given regular counselling to maintain motivation. One of the effects of this was that most women decided for themselves to actually start eating less as well. On average they consumed 360 calories less each day than when the started the study.
The result of all of this after eight years showed that on average these women lost 2 pounds each, but their average waist circumference increased! This would suggest that the weight lost was actually lean tissue (muscle) and not fat.
Tuffs University conducted a study in 2007, which was an analysis of all relevant diet trials since 1980 – the single largest such trial ever done and concluded that low-calorie diets for obese and overweight people leads to at best “modest weight losses” that are “temporary”. Typically 9-10 pounds are lost in the first 6 months. After one year most of this has been put back on.
This is backed up in the book “Handbook of Obesity” edited by three of the most prominent experts in this field – George Bray, Claude Bouchard and WPT James who state that “Dietary therapy remains the cornerstone of treatment and the reduction of energy intake continues to be the basis of successful weight reduction programmes” – In other words reducing the calories that you eat each day is the best way to lose weight.
But then only a few paragraphs later it contradicts itself by saying “that the results from such energy reduced restricted diets are know to be poor and not long lasting”!!!
Up until the 70’s ‘reduced calorie’ diets were known as ‘semi starvation’ diets as this is what people end up doing. The problem with this, as has been proven time and time again is that you cannot ‘semi starve’ yourself forever. So if you should be eating 2000 calories per day and go on a diet that reduces calories to only 1000 calories per day then should it really come as a surprise that you put weight back on when things go back to normal and start eating 2000 a day again.
The most interesting conclusion that I draw from this though is that if under-eating is not the cure to obesity then surely ‘overeating’ is not the cause.