Having a glass of skim milk instead of fruit juice at breakfast may help people feel more full all the way up to lunch, a small study suggests.

Australian researchers found that when they had 34 overweight adults drink either skim milk or juice with breakfast, the participants generally felt more satisfied - and downed fewer calories at lunch - on the day they had milk.

The reasons for the findings are not completely clear. However, one possibility is that the proteins in milk are more effective in satisfying people’s appetites than are the sugars in fruit juice, the researchers report in the American Journal of Clinical Nutrition.

Often, people avoid dairy products when they are trying to cut calories and lose weight, noted lead researcher Dr. Emma R. Dove, of the University of Western Australia in Perth.

However, she told Reuters Health, the “core message” of this study is that low-fat dairy, like skim milk, may help keep a person’s appetite under better control when used in place of a more sugary item with similar calories.

For their study, Dove and her colleagues tested 34 overweight men and women on 2 separate days, 1 week apart. On one day, participants had a breakfast of toast and jam, along with a glass of milk; on the other day, the toast came with a glass of fruit juice.

On both days, participants were later given lunch and asked to eat until they felt comfortably full. They also rated their hunger before breakfast, at several points throughout the morning, and again after lunch.

Overall, the study found, the men and women tended to feel more satisfied after their milk breakfast. What’s more, they ate an average of 8.5 percent fewer calories at lunch. The calories consumed at lunch were higher among the fruit juice drinkers than in the milk drinkers, and the difference was statistically significant.

Some previous studies have suggested that proteins in general are more satisfying and act as stronger appetite suppressants than carbohydrates. It’s possible that there is something about milk proteins, in particular, that help control appetite, Dove said, but the study did not look at that question.

New Zealand-based Fonterra Brands Pty Ltd., a dairy product manufacturer, funded the research.

SOURCE: American Journal of Clinical Nutrition, July 2009.