One key to successful weight control is to eat foods that, calorie for calorie, are most satisfying. Two factors that have identified as having some importance here are the glycaemic index of a food and its protein content. Basically low glycaemic index (GI) foods (those that release sugar relatively slowly into the bloodstream) are more satisfying than higher GI food. Also, calorie for calorie, protein is generally more sating than carbohydrate or fat. It’s perhaps no surprise, therefore, that when individuals opt for a low-carb, protein rich diet, they often report feeling less hungry and eating less (without hunger) as a result.
Recent evidence suggests that another nutritional factor that might influence our ability to be satisfied after a meal is the so-called omega-3 fats found in oily varieties of fish such as salmon, trout, mackerel and sardine. In a study published in the journal Appetite, 233 overweight and obese individuals (average age about 30) were put on an energy-restricted (lower calorie) diet for a period of eight weeks. During the last two weeks of the diet, individuals were assigned to a diet rich in omega-3 fats (1300 mg or more of omega-3 fat per day) or low in omega-3 fat (less than 260 mg of omega-3 fat per day). The sating effects of a meal were tested immediately after eating and two hours later. The omega-3 fat levels red blood cells was also measured.
Eating more omega-3 fats did translate into higher omega-3 fat levels in the blood. Importantly, compared to those eating the low-omega-3 diet, those eating the diet rich in omega-3 were found to feel fuller immediately after an evening meal. Two hours later, these individuals were still fuller and were less hungry compared to those consuming less omega-3 fats in their diet. The authors of this study concluded that omega-3 fat intake enhanced post-meal satiety, and called for further work to be done to ascertain whether this approach might improve weight loss.
One way to get more omega-3 into the body is to eat more oily fish. I suppose it is worth bearing in mind that such food is low GI and protein-rich, and may have appetite-sating effects related to these qualities too.
Parra D, et al. A diet rich in long chain omega-3 fatty acids modulates satiety in overweight and obese volunteers during weight loss. Appetite, 2008 Jun 14; [Epub ahead of print]