Weight Drops On Low Carbs With More Fat Or Protein

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Weight Drops On Low Carbs With More Fat Or Protein

Last Updated: 2005-04-21 11:37:05 -0400 (Reuters Health)

By Amy Norton

NEW YORK (Reuters Health) - People who cut carbohydrates in order to lose

weight do equally well whether they compensate with increased amounts of

animal

protein or plant-based fats, a new study suggests.

Australian researchers found that a low-fat, high-protein diet and a

high-fat, moderate-protein diet were equally successful in helping 57

overweight and

obese volunteers shed pounds over three months.

Both regimens, which restricted carbs to a moderate degree, also showed

similarly positive effects on the dieters' levels of cholesterol, blood

sugar and

insulin,

the key hormonal regulator of the body's blood sugar levels.

The findings, say the researchers, show that people have some choices when

it comes to carb-cutting.

The low-fat, high-protein diet used in the study was based on fairly

generous portions of lean meats and fish and low-fat dairy products. The

high-fat version

was rich in monounsaturated fats from canola oil and nuts, and contained

more-moderate amounts of lean meat and dairy.

Both meal plans kept carbohydrates to about one-third of the dieters' daily

calories, and included fruits, vegetables and even a slice of whole-grain

bread.

" The implication of these findings, " the study authors report in the

American Journal of Clinical

Nutrition, "

is that protein from meat, poultry and dairy foods or fat from food sources

rich in monounsaturated fatty acids are both suitable options to replace

some

dietary carbohydrate, at least in the short term. " ]

A number of studies have suggested that low-carb diets spur weight loss more

quickly than low-fat diets do. Proponents of carb-cutting say the diets

force

the body to switch from using mainly using

glucose

(sugar) for fuel to burning its stored supplies of fat instead.

However, many questions about low-carb diets remain -- including whether the

eating plans keep the weight off and whether they might have ill effects on

health in the long term.

Some experts worry about the eventual effects on the heart and blood

vessels, particularly when people follow diets that are heavy in saturated

fats from

meat and dairy products. In addition, the metabolic effects of high-protein,

high-fat diets may deplete minerals in the bones or

stress

the kidneys.

Another question has been whether it's best -- as far as weight loss and

overall health -- to replace some of the lost carbohydrates with protein or

fat.

In the current study, it did not matter, Dr. M. Clifton of the

University of Adelaide told Reuters Health.

He and his colleagues found that after 12 weeks on either diet, men and

women lost a similar amount of weight -- more than 20 pounds, on average.

They did

not, however, shed any weight during an additional four-week period where

they replaced carbs with protein or fat but did not cut their calorie

intake.

In addition to the weight loss, dieters' levels of blood cholesterol and

insulin fell with either plan, and there were no signs of short-term harm to

participants'

bones or kidney function from either diet.

However, as Clifton pointed out, neither diet was " radical, " with each being

relatively low in the saturated fat and balanced in nutrient content.

" Either

diet would be sustainable in the long term, " he said.

There was, though, one subtle difference potentially in favor of the

high-protein tactic, at least in terms of weight loss. Men and women on that

diet showed

a smaller decrease in a measure called the " thermic effect of feeding. " This

means that they used more calories simply metabolizing their food than their

peers on the high-fat diet did.

It's possible, Clifton said, that over one to two years, the high-protein

diet could end up spurring greater weight loss.

SOURCE: American Journal of Clinical Nutrition, April 2005.