It's not how much fat, but where it is that's important

This new study suggests that it is actually overeating and not the obesity that is caused by overindulgence, that is the trigger for metabolic syndrome. It is how and where the body stores excess calories that is most important when determining a person's risk of the syndrome.

Professor Roger Unger and colleagues from UT Southwestern compared mice who were genetically altered to prevent their fat cells from expanding when overfed to mice with no such protection against becoming obese. researchers compared mice genetically altered to prevent their fat cells from expanding when overfed to mice with no such protections against becoming obese. The normal mice got fat when overfed, but didn't develop signs of metabolic syndrome until about seven weeks into the experiment, at about 12 weeks of age.

The mice engineered to remain slim, however, enjoyed no such "pre-diabetic honeymoon period," the study authors said. Some became seriously ill at four to five weeks of age and displayed evidence of severe heart problems and marked hyperglycemia by 10 weeks of age, a full eight weeks before the normal mice displayed even minimal heart problems. The genetically altered mice also suffered devastating damage to heart cells and to the insulin-secreting cells in their pancreas.

According to one of the lead researchers the mice engineered to stay slim got sick quicker because the extra calories were not stored in the fat cells, the one place in the body equipped to store fat. Instead, fat was stored in other tissues, mimicking what happens in people with congenital generalized lipodystrophy.

This suggests that if you are going to overeat, you are likely to be healthier if your body can store the fat in fat cells, rather than in other parts of the body. This in no way says that obesity is OK - but it does suggest that the health consequences of being overweight result from a more complex mechanism than initially thought.