Ghrelin is a recently discovered hormone produced by the stomach and other parts of the gastrointestinal (GI) tract. High levels of this hormone are released by the GI tract into the blood and correlate with subjective feelings of hunger. When ghrelin is given to people intravenously, it increases their hunger level and causes them to eat significantly more calories at meal than when given a placebo. Ghrelin is one of the first hormones that has been shown to stimulate appetite. It seems to be involved in shot-term satiety after a meal and in long-term hunger and food intake regulation as well. It is one of the most promising biomarkers yet discovered for hunger and food intake regulation.1
When people lose weight on calorie-restricted diets, ghrelin levels increase and people report they are hungrier than before they lost the weight. In one study ghrelin levels rose 24% after subjects lost 17% of their initial body weight. Eating food dramatically lowers ghrelin levels in the blood and eliminates hunger. But simply drinking water does not lower ghrelin levels and does not reduce hunger. Not all foods have the same impact on ghrelin levels.
• Ghrelin levels drop in proportion to the amount of carbohydrate in a meal or snack.
• The consumption of fat or a fat-rich meal does not suppress the release of ghrelin nearly as effectively as does a meal with more carbohydrate and little fat. This may explain why most people who lose body fat and keep it off do soon fat-restricted diets.2
• Fructose, like fat, suppresses ghrelin less than glucose suggesting it too may contribute to overeating and weight gain.3
Bottom Line: Research on ghrelin suggests that people are more likely to be able to control their appetites and lose weight and keep it off without having to deal with increased hunger if they consume less fat and fructose.
By James Kenney PhD, RD, LD, FACN.
1. Am J Clin Nutr 2004;79:946-61
2. J Clin Endocrinol Metab 2003;88:1577-88
3. J Clin Endocrinol Metab 89(6):2963–2972
Judy’s passion for cooking began with helping her grandmother make raisin oatmeal for breakfast. From there she earned her first food service job at 15, was accepted to the world famous Culinary Institute of America at 18 (where she graduated second in her class), and went on to the Fachschule Richemont in Switzerland where she focused on pastry arts and baking. But after learning that the quality of a croissant directly varies with how much butter it has, Judy sought to challenge herself by coming up with recipes that were as healthy as they were tasty.
Judy received The Culinary Institute of America’s Pro Chef II certification, the American Culinary Federation Bronze Medal, Gold Medal, and ACF Chef of the Year. Her enthusiasm for eating nutritiously and deliciously leads her to constantly innovate and use the latest in nutritional science to guide her creativity, from putting new twists on fajitas to adapting Italian brownies to include ingredients like toasted nuts and cooked honey. Judy’s publishing company, Food and Health Communications, is dedicated to her vision that everyone can make food that tastes as good as it is for you.