Scientists reveal low-carb diets reduce appetite

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Scientists reveal low-carb diets reduce appetite

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16.03.05

By JEREMY LAURANCE

 

 

Scientists have discovered why the Atkins diet is so successful at

helping people lose weight.

 

Curbing carbohydrates actually reduces overall appetite so people on

Atkins-type diets shed more kilograms more quickly, research has shown.

 

The small study involved just 10 volunteers who were confined to

hospital for three weeks so that every calorie they consumed and expended

could be measured.

 

It revealed that carbohydrates eaten by the volunteers - potatoes,

bread and cakes - stimulated their appetite so they ate more of other foods

as well.

 

When the carbs were restricted, consumption of other foods fell as

well, even though the volunteers were free to eat anything else they wanted.

 

Over the three weeks of the study the average daily consumption fell

by a third from 3111 calories a day to 2164 calories, when access to

potatoes, bread and cakes was restricted. The volunteers, who were obese and

had diabetes, lost 1.6kg on average.

 

Many claims have been made about the way the Atkins diet disrupts the

body's metabolism to encourage weight loss. But Guenther Boden, professor of

medicine at Temple University, Philadelphia, who led the study, said this

was a myth.

 

" We proved that people lose weight on the Atkins diet because they eat

less, not because the carbohydrate calories are treated differently by the

body, " he said.

 

" Participants went from an excessive caloric intake to a normal

caloric intake for their height and weight when we reduced their

carbohydrates. This indicates to me that it was the carbohydrates that

stimulated the excessive appetite. "

 

At the start of the study the volunteers were eating 300g a day of

carbohydrates but these were cut to 20g a day at the end of the first week.

 

Overall consumption fell by 1000 calories a day, even though the

participants were offered as much protein and fatty foods as they could eat.

 

The researchers weighed all food, monitored exercise and measured

calorie energy intake, expenditure and body water composition and tested

blood sugar, cholesterol and hormone levels believed to be involved in

appetite regulation.

 

" All the weight loss was in fat, " Professor Boden said. " We weighed

and measured every calorie that participants ate and every calorie they

spent. We knew what went in and what went out.

 

" On the very low carbohydrate diet participants spontaneously reduced

their calories by about 1000 a day. One gram of fat equals nine calories so,

doing the maths, you can determine how much fat will be lost by cutting 1000

calories. "

 

He added: " You don't have to cut carbs as drastically as participants

did. If you cut carbs modestly, you cut calories and you'll lose weight.

 

" It helps to know that carbohydrates make it more difficult to reduce

food intake. So cutting the carbohydrates at least to some extent will help

keep down the caloric intake.

 

" With fewer carbohydrates you are going to eat fewer total calories a

day. "

 

The study is published in Annals of Internal Medicine.

 

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