Carbs or Fat: Which is Worse?

For years, health officials and nutrition experts have been telling us that the way to a smaller waistline is to cut the amount of fat in our food. But the latest studies have found that dietary fat doesn’t necessarily have a big impact on body weight.

“People eating the most fat are not significantly heavier than people eating the least amount of fat,” says David Ludwig, M.D., Ph.D., of the Optimal Weight for Life Program at Children’s Hospital in Boston. “And people eating very little fat may be getting a lot of refined food and sugar. The fat-free Twinkie takes out the fat calories, but puts in more sugar and starch.”

Ludwig has written numerous scientific articles on what he sees as a bigger culprit in the current epidemic of overweight and obesity: foods with a high glycemic index.

“When you eat a lot of refined starch, especially if the meal is low fat, the starch breaks down into sugar rapidly,” Ludwig says. “This leads to an abrupt rise in blood glucose levels over the next half hour to an hour (after eating), which causes a lot of insulin to be released from the pancreas into the blood stream to drive sugar down to normal levels.”

But with high starch or refined foods, the pancreas tends to “overshoot” insulin into the bloodstream, driving blood sugar levels below the normal level.

“When a person’s blood sugar is very low, he can feel hungry, have difficulty concentrating and become fidgety,” Ludwig explains. “Between meals, he’s more likely to say yes to an extra treat or a snack he’s seeing in the hallways in school. And, in doing so, he’s getting unnecessary calories. Just 100 extra calories a day can cause a difference in body weight of 10 pounds over a year.”

Carbohydrates consumed in their most natural state – such as in fruit and vegetables – are best, Ludwig says. Those in refined foods and sugars should be avoided.