LOW FAT DIETS CAN HARM SOME PEOPLE
Report #6549 7/10/95
A low-fat diet is supposed to lower your cholesterol and help you lose weight, yet/ when some people go on low-fat diets, they gain weight and increase their chances of developing a heart attack by lowering blood levels of their good HDL cholesterol and raising blood levels of triglycerides.
A low-fat diet helps you lose weight and prevents heart attacks only if it forces you to take in fewer calories. If you increase your caloric intake on a low-fat diet, you will gain weight. When you take in more calories than your body uses, the extra calories are converted to fat by your liver. It makes no difference to your liver whether the extra calories come from carbohydrates, fats or proteins. To reduce your intake of calories on a low- fat diet, you have to take in lots of fiber which are the only component in food that fill you up without contributing calories. A low-fat diet helps you to lose weight only if you eat lots of fruits, vegetables, whole grains and beans.
Carbohydrate foods that are low in fiber, such as pasta, cous cous, breads, low-fat pastries and ice creams can cause you to gain weight and increase your chances of suffering a heart attack. The people who are most likely to gain weight on a low-fat, low-fiber diet are those who store fat primarily in their bellies, have low blood levels of the good HDL cholesterol and high levels of triglycerides, and have a family history of diabetes. That's why in the last decade, the average American has reduced his intake of fat from 41% to 34%, yet has gained 8 pounds.
By Gabe Mirkin, M.D., for CBS Radio News
1) BL Heitmann, L Lissner, TIA Sorensen, C Bengtsson. Dietary fat intake and weight gain
in women genetically predisposed for obesity. American Journal of Clinical Nutrition 61:
6(JUN 1995):1213-1217
2) PT Williams, DM Dreon, RM Krauss. Effects of dietary fat on high-density-lipoprotein subclasses are influenced by both apolipoprotein E isoforms and low-density-lipoprotein subclass patterns. American Journal of Clinical Nutrition 61: 6(JUN 1995):1234-1240. Replacing dietary fat with carbohydrates 1) significantly decreased HDL(3a), HDL(2a), and HDL(2b); 2) reduced HDL(2b) significantly more in pattern A than in pattern B men; and 3) increased plasma HDL(3b), concentrations significantly more in those men with the epsilon 2 allele. Our results suggest that unfavorable HDL changes were significantly more likely to occur in men who had LDL-subclass pattern A or the apo epsilon 2 allele than in men who had pattern B or lacked the epsilon 2 allele.