Research into the genetic basis of diet, weight gain/loss, food intolerances etc has been going on for decades. I have heard several programmes on R4 discussing this research, may be as long as 5 years ago.
It has long been known that the previous simplistic belief that calories in can be equated to calories out plus weight gain and its reverse that eating less will infallably lead to weight loss is wrong, scientists now are beginning to unravel the way our genes can affect our eating patterns. Tim Spector's recent research into the human biome is another contributor to the unravelling of the complexities with the way the body processes the food we eat. We have long known that certain ethnic groups have difficulty metabolising cetain foods and 90% of Japanese people are lactose intolerant.
We also now know that there a levels of food intolerances. All my life fresh milk and lightly processed dairy products like yoghourt have made me nauseous, if not sick, yet I love and can eat as, much hard cheese, as I like. Recently an article in the New Scientist said that it has been recognised that there is a large group of people like me and the cause is a mild lactose intolerance, that fades the more processing the milk has had.
As to who pays for the research, it is like any other research, funding comes from a variety of sotces, chaariyable foundations, special disease interest societies, individula donors, government departments and from industry itself.
All reputableacademic journals ensure that all articles they accept have been peer-reviewed by other experts in the field that the editor chooses, not the researcher, and while errors do ocur, connsidering the amount of peer-reviewed journal articles published each year, the fraud and error rate is very low.