Just 2 pounds of weight gain can greatly increase a person's risk for the metabolic syndrome, a dangerous condition that can lead to type 2 diabetes and coronary heart disease. Now the French may be headed for similar problems. The new study, led by an American researcher working with scientists at France's Institute National de la Sante et de la Recherche Medicale (INSERM), followed a normal-weight group of 3,770 French men and women for six years. They found that each kilogram (2.2 pounds) of weight gain increased the risk of the metabolic syndrome by 22 percent. After six years, 21 percent who gained nine kilograms or more (19.8 pounds or more) developed the syndrome.
From a public health perspective, it is especially important to note that the more pounds normal-weight people gain, the more their risk increases for developing the metabolic syndrome. Secondly, insulin levels had the greatest proportional increase among all metabolic syndrome parameters across all weight-change groups, nearly doubling for both men and women. "This is important new information because it shows that even mild weight gain is associated with insulin resistance," says Hillier, lead author of the article Finally, she notes, "many people whose weight remained stable or who lost modest amounts of weight did not develop the metabolic syndrome."
The study included adult participants aged 30-64 at baseline who were recruited between 1994 and 1996 from 10 government health examination centers in western-central France. After six years, there was an average worsening in both men and women in all measures -- weight, BMI, waist girth, glucose, insulin, HDL cholesterol, and blood pressure -- except for HDL cholesterol in women.
"These findings show that even modest weight gain in normal-weight people is an important indicator for the metabolic syndrome and thus for diabetes and heart disease risk," says Hillier. "They also tell us that we need to pay particular attention to even modest increases in weight and waist circumference, which had a marked impact on increasing insulin levels (or insulin resistance)."
For France, which has had the lowest prevalence of obesity among nine northern European countries and among the lowest of Westernized countries in the world, these results raise some important social and cultural questions. The so-called French paradox -- the belief that there is something in the French lifestyle, red wine perhaps that protects them against obesity, heart disease, and diabetes -- may be a myth or it may be a truism that is passing into history. As more and more French men and women adopt a lifestyle that is increasingly American -- fast foods, processed foods, more soda pop and caloric intake, little or no exercise -- they may be entering the front end of the obesity and diabetes epidemics that began in America nearly 20 years ago.