The researchers suspect that milk's protein content (providing 16 per cent of the daily value per cup), the lactose (the natural sugar in milk) or simply the thickness of the beverage may play a role in the satiety benefits and suggests that choosing foods that can help enhance satiety is an important success factor in any weight management plan.

The researchers say experts are increasingly focused on small behaviour changes that can make a significant difference when it comes to maintaining a healthy weight and a decrease of as little as 50 calories per day can accumulate in the long term.

They say fat free milk is loaded with nine essential nutrients, including calcium and vitamin D, and contains 80 calories per 8-ounce serving - most dietary guidelines recommend three servings of fat free or lowfat milk each day.

The researchers say several studies have shown that proteins, including whey and casein, are more satiating than carbohydrates which suggests that skim milk would be more satiating than sugar-rich beverages.

The study which is published in the July issue of the American Journal of Clinical Nutrition was supported by the New Zealand milk producer Fonterra.