Fruit consumption and BMI

Like all developed countries of the world, the US has a massive obesity problem having profound negative health effects. Questions posed in a USDA study (Food Review, 2002, 25, 28-32) were – do the overweight/obese eat differently from thinner people ie choose different foods or consume larger quantities or both? Or is it a result of metabolism and activity level or all of these things? Government agencies and medical societies have been urging Americans for years now to eat more fruits and vegetables, both in quantity and variety, as healthy substitutes to improve their usual diet mix of high calorie foods. So the USDA looked at the relationship between consumption of fruits and veges and obesity in 4709 men and 4408 women over the age of 19, and tracked them over a 3 year period to assess their regular eating habits. BMI (body mass index) was used as the measure of obesity.

They found that the more fruit regularly consumed (measured as no of servings, including whether eaten as single foods or incorporated into food products eg blueberry muffins) the less likely they were to be overweight or obese. But they didn’t find any significant change in BMI with increasing consumption of veges. A surprising result given that on average veges are even lower in calories than fruit. And worse still, when potatoes were examined separately from all other veges, the more of these they ate the fatter they were.

They concluded the explanation was in the way veges are normally eaten. Fruit are most often eaten raw or as juices without the necessity of processing as they’re sufficiently edible and sweet by themselves. Although veges are also eaten fresh in salads and juices, they are more often processed/cooked in different ways before eating. They suggested that Americans may too often deep-fry their veges (think French fries), top them with high-fat dressings or sour creams, or include them in other high fat culinary delights. Another contributor they mentioned was that some people who are in the habit of having morning and afternoon snacks could be eating fruit rather than biscuits, chocolate bars, cakes or other high cal foods. Fresh veges don’t have the same attraction as fruit for such a substitution.