A new report, The Link Between Local Food Environments and Obesity and Diabetes, just published by the California Center for Public Health Advocacy (CCPHA), has summarised and confirmed the results of the 2005 California Health Interview Survey (CHIS).

It shows a clear link between High Retail Food Environment Index (RFEI) scores and the amount of both obesity and Type 2 diabetes in a neighbourhood.

The RFEI is made by dividing the total number of fast-food restaurants and convenience stores by the total number of grocery stores and local produce vendors in the area, so reflects the proportion of people eating diets with less fruit and vegetables.

The average Californian has easy access to four times as many fast-food restaurants and convenience stores as grocery stores and produce vendors.

Obesity rates are 20 percent higher for Californians with RFEIs of five and above compared to those with RFEIs below three.

Diabetes rates are 23 percent higher for Californians with RFEIs of five and above compared to those with RFEIs below three.

Nearly half of Californians have three times as many fast food outlets as fresh food outlets near them.

Pretty shocking eh?

Although some people have contested results like this in the past, it seems fairly clear to me that high carbohydrate, high trans-fats diets are a sure-fire recipe for putting on weight. and developing diabetes.
DESIGNED FOR DISEASE: The Link Between Local Food Environments and Obesity and Diabetes. The California Center for Public Health Advocacy, PolicyLink and The UCLA Center for Health Policy. 2008.

Interesting commentary in the Journal of the American Medical Association recently about how abnormal fat metabolism is the root cause of Type 2 diabetes. The author suggests that accumulation of fats in body cells causes insulin resistance and therefore Type 2 diabetes. The fats, he says get deposited in body cells because people eat too much, and he’s probably right, but he doesn’t address the question of what sort of eating too much is particularly bad for you. The current view seems to be that excess calories make you fat, and that since dietary fat contains 9 kcal per gram, this is worse than carbohydrate, which has about 4 kcal per gram, but in fact, what really cause fat to be laid down in cells is insulin, and this is only produced when you take in carbohydrate. So, the theory may be right, but the detail, as always is vital to the message.

 The report is by Unger, JAMA, March 12 2008, Vol 299, No 10, 1185-7.

I just came across a very interesting report in the Journal of the American Medical Association (JAMA) from January this year. This was a controlled trial of surgery (gastric banding) comared with conventional weight loss treatments in obese people with Type 2 diabetes.

The conventionally treated group lost less than 2% of their weight on average, although there was some improvement in their diabetes in those who lost more than 10%. The surgical group lost an average of more than 20% of their weight over the 2 year study period, and a stunning 73% of them had complete remission of their diabetes, with no serious complications of the surgery.

Strong evidence indeed that weight loss is the key to improving control in Type 2 diabetes, although it is disappointing that the results in the diet alone group were so poor and that they lost so little weight. The diet, however, was the usual “balanced” diet still usually recommended by dieticians for wieght loss, and I wonder what would have happenned if a low carbohydrate approach had been used. We can’t use gastric banding on everybody!

The reference is Dixon et al. JAMA Jan 23, 2008. Vol 299 No3. 316-323.