Bssh wrote: I've not read up on her research but perhaps her studies only focussed on weightloss and weightloss outcomes and not on health benefits per se hence her not talking about the health benefits of the actual fasting itself. Mosley based his thoughts on other researchers eg Longo and Mattson who (if I recall correctly) focussed on the health aspects.
Her research does show that there is a preferential fat loss from the abdomen and preservation of fat-free mass (i.e., everything that isn't fat including muscle). Because obesity is related to so many health problems, losing weight, however you do it, would be expected to be associated with improvements in these health problems.
However, as you might expect, it's a bit more complicated than that! There is a school of thought that abdominal obesity is a symptom of insulin resistance rather than a cause (like a bruise is a symptom of a knock not the cause of it). Insulin resistance is reduced by calorie restricted diets, so the health benefits that are seen alongside the loss of fat are due to the improvement in insulin resistance rather than the fat loss itself. Thus, it is the diet not the loss of weight that brings the health benefits. This is probably why a reduction of as little as 5% of body weight can bring substantial benefits. Fasting (and low carbing) are more effective at lowering insulin and reversing insulin resistance than other diets and so would be expected to bring greater health benefits than other diets and this will be reflected in bigger losses in abdominal fat, which is, in fact, what we do see.
The theory that weight loss alone results in health benefits can be investigated by looking at what happens if you surgically remove fat by liposuction. What happens is that there is no improvement in insulin resistance and other cardiovascular risk factors as this study shows:
http://www.ncbi.nlm.nih.gov/pubmed/18820648Body composition and metabolic risk factors for CHD, including oral glucose tolerance, insulin resistance, plasma lipid profile, and blood pressure were evaluated in seven obese (39 +/- 2 kg/m(2)) women before and at 10, 27, and 84-208 weeks after large-volume liposuction. Liposuction surgery removed 9.4 +/- 1.8 kg of body fat (16 +/- 2% of total fat mass; 6.1 +/- 1.4 kg decrease in body weight), primarily from abdominal SAT; body composition and weight remained the same from 10 through 84-208 weeks. Metabolic endpoints (oral glucose tolerance, homeostasis model assessment of insulin resistance, blood pressure and plasma triglyceride (TG), high-density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol concentrations) obtained at 10 through 208 weeks were not different from baseline and did not change over time. These data demonstrate that removal of a large amount of abdominal SAT by using liposuction does not improve CHD metabolic risk factors associated with abdominal obesity, despite a long-term reduction in body fat.
Further, we can see that fasting itself can bring health benefits from the studies by Valter Longo on the 5-day once a month fast. The participants gained back the weight they lost during fasting but they gained health benefits that persisted.
