By Michael R. Williams, RD

Soup is a well-known nourishing tradition. When winter’s brisk winds begin, a hearty bowl can keeps us warm, well and healthy. And when feeling under the weather, chicken noodles become a common cure. What is not so well known is that having a bowl of soup each day can help stave off winter weight gains.

The secret to soup’s weight loss success is satiety. Satiety is the feeling of fullness that comes after a meal. This fullness occurs from a mixture of physical and psychological factors that include the physical filling of the stomach and the rush of appetite-decreasing hormones. Foods with high satiety keep us from coming back for second helpings and instead spare more calories.

One of the highest satiety factors is water. But it is not the water that you drink, many studies have shown liquids have a very low influence on satiety. Instead, water found in food is the most satiating. This is one reason behind the mainstay fruits and vegetables in weight loss. Nonetheless, a wealth of research on satiety and weight loss has centered on the surprisingly high satiety of soup, a watery food.

The research on soup and satiety started over 20 years ago at Penn State. In a groundbreaking study, eating a small (200 calorie) bowl of soup before a meal significantly reduced the overall amount eaten. Since then many ideas have been proposed to understand why soup acts this way. Even though we are still far from a complete understanding, continual studies keep showing the same results: Eating soup before a meal decreases overall intake.

A recent study in the European Journal of Clinical Nutrition explored the types of soups that best reduce overall food intake. This study of over 20 healthy volunteers measured three different meals: a solid meal, a chunky soup and a smooth soup. Each meal was made of the same amount of rice, chicken and vegetables but prepared in different ways. Measurements were made to see how quickly food left the stomach and how full each participant reported feeling. The study found that smooth (blended) soup left the stomach more slowly and significantly increased overall satiety compared to the chunky soup and solid food.

Eating fewer calories is the cornerstone to weight loss. One of the best ways to cut back is to choose foods that are high in water, rich in fiber and low in calories. The current research shows that having a small salad or a bowl of soup before a meal can help increase fullness and lead to less calories consumed. More specifically, clear, smooth soups before each meal can help calm an increased appetite.