There was a very interesting programme on tv last night, a Horizon investigation into fat and sugar in the diet and what damage each was responsible for in the body. Identical twin doctors, Chris and Xand, each followed a prescriptive diet, one high in fat and one high in sugar/carbs. There were some surprising outcomes, like the way that the high fat/no sugar diet brought that twin closer to pre-diabetes than the twin who ate a high sugar diet. That was eye-opening. They shared the reasonable idea that fad diets which exclude whole food groups are in the long term unsustainable and probably not that healthy.
The real point, for me, of the programme was the information that the fat and sugar combination is the real killer. A 50:50 balance of fat and sugar in a food apparently makes that food almost irresistable to us, and also switches off the natural "I'm full" feeling that either fat or sugar gives when consumed separately. Given that they said that this combination is unavailable in nature and only occurs in processed food, it seems that the modern drive for processing and convenience may be what is making the developed world fat.
Food for thought, if you'll pardon the pun!