What food component would be better restricted to lose weight and improve health- fat or carbohydrates? This is an on going battle. Low-fat Living or AtkinsDiet? Today we discuss the first part - low-fat diets.

Subscribe to be notified about the next article on diets. It's time to look at the available scientific evidence supporting these diametricaly opposing postions. Let's see what both sides state.

High-fat diets cause obesity and low-fat diets can reverse it. True or false?

Believe it or not - neither one.

Scientists at the Department of Internal Medicine of Goteborg University, Sweden, reviewed a multitude of epidemiological data on dietary fat and obesity. This is what they found (Eur J Clin Nutr, 49(2):79-901995).

When researchers analyzed how habitual menus influence body weight, the greater fat intake, the heavier the population pattern seemed to emerge:think they could see that the greater fat intake, the heavier the population:

"Cross-sectional studies are generally in agreement that the concentrationof fat in the diet is positively associated with relative weight." When various changes in diet fats are analyzed, no consistent results were obtained"

"Prospective studies of diet in relation to subsequent weight change giveinconsistent results. This may be due to behavioural factors such asdieting in response to weight gain"

"Intervention studies in free-living subjects are considered, providingevidence of a consistent but short-lived period of active weight loss onlow-fat diets."

To cut fat, calories or both?

Help yourself! In this case, you may eat asmuch as you want.

This is what experts at the Center on Aging at Tufts University say(JAMA, 274(18):1450-5 1995).Switching from the average US diet of 35.4% total fat to low-fat diet of 15.1%total fat without weight loss (people in this group were forced to eat to maintain their pro-program weight) decreased bad cholesterol levels, but it significantly decreased the good cholesterol also.

"Consumption of the low-fat diet under weight-maintenance conditions hadsignificant lowering effects on plasma total cholesterol low-densityand high-density lipoprotein cholesterol levels (-17.1%, and -22.8%, respectively)."

However, when the low-fat plan allowed eating as much the subjects pleased - they ate less than the previous group! They decreased their bad cholesterol while preserving the good one.

"Consumption of the low-fat ad libitum diet was accompanied bysignificant weight loss (3.63 kg), by a mean decrease in low-density(124.3%) and high-density cholesterol that were not significantly different from the baseline.."

Low-fat, high-carbs?

High oils instead of high-carbs is a better option, if you want to prevent heart diseases.Especially if you cut down on carbohydrates.At the Department of Human Nutrition, Wageningen Agricultural University,Netherlands, researchers investigated the input of high-carbohydratecomponents of a low-fat diet which was intended to keep the caloric count adequateto the normal energy needs. They concluded that weight loss with low-fatdiets is modest and insufficient to balance the fall in the good(high-density lipoprotein) cholesterol. < Am J Clin Nutr, 274(4Suppl):974S-979S 1997).

"Low-fat, high-carbohydrate diets lower plasma low-density lipoprotein butalso lower high-density lipoprotein concentrations and raise plasmavery-low-density lipoprotein. The predicted net effect on coronaryrisk is zero."

"In contrast, diets low in saturated fat but high in unsaturated oilsimprove the ratio of high to low-density lipoprotein in plasma and thusreduce the predicted coronary risk."

Low-fat, high-sugar?

Yes, if you cut down on calories and want to be in a good mood.This is what psychiatrists at Duke University Medical Center figured out.( Am J Clin Nutr, 65(4):908-15 1997). They looked at two diets that were similar in energy, fat and protein, but one was much sweeterthan the other.

"The diets contained approximately 4606 kJ energy/d with 11% of energyas fat, 19% as protein, and 71% as carbohydrate. The high-sucrose dietcontained 43% of the total daily energy intake as sucrose; thelow-sucrose diet contained 4% of the total daily energy intake assucrose."