Eat a high-protein diet to decrease food cravings and achieve optimal body composition. It is well known that a high-protein diet can help you lose fat and gain muscle, but it’s always good to be reminded, especially as we enter peak beach season (many prime opportunities to show off your physique AND lots of chances to be enticed by snacks you’d rather not eat).
A new article in the journal Nutrition Research Reviews analyzes how a high-protein diet improves body composition. First, there’s the direct effect of thermogenesis on weight control. The more protein you eat, the greater the energetic cost necessary to incorporate each amino acid into lean tissue. By eating protein your body burns significantly more calories than if you had eaten the same amount of fat or carbs.
The second benefit of eating high-quality solid protein regularly throughout the day is that you can decrease feelings of hunger, and studies show it leads people to choose to eat less total calories. Appetite is decreased by the feeling of fullness and satisfaction—it doesn’t just take place in your stomach but is greatly influenced by the brain’s response and association to the experience of eating. As soon as you put something in your mouth and swallow it, gut peptides send messages to the brain.
There is evidence that certain foods—carbohydrates in general but especially sugary or salty foods—result in chemical messages to the brain that cause us to eat more and continue the “rewarding” or “pleasurable” experience of food.
By eating a high-protein diet, the opioid and GABA chemical messages are not active, which is thought to reduce the hedonic or pleasurable response to food. Don’t be deterred by this—some people may shy away from a high-protein diet because they want to have a pleasurable “food experience,” but there are many ways to make high-quality protein meals that are flavorful, will support brain function, and body composition.
Additionally, it’s unclear that high-protein diets are not pleasurable since we know that they are typically high in tryptophan—the amino acid that is a precursor for serotonin, which makes us feel good. Perhaps the difference is that high-protein diets are not addicting and they don’t cause us to binge or eat excessive amounts.
Finally, hormonal signals relative to the status of energy stores are lowered or elevated by the macronutrient content of food. I’m sure you know that carbohydrates will elevate insulin dramatically but won’t elevate leptin as much. Leptin is the hormone that inhibits hunger and elevates fat burning in the body, and it is rather telling that the word “leptin” is Greek for “thin.” Protein will elevate leptin, decrease ghrelin, which stimulates hunger, and won’t elevate insulin.
For best results with a high-protein diet, plan meals carefully so that you get high-quality protein at every meal and at snacks. Pair protein with slow-digesting carbohydrates, especially green vegetables, and smart fats. Shoot for solid protein except for pre- and post-workout shakes because solid protein has been shown to have a much more satiating effect.
If you do take liquid protein before and after training, whey has been shown to blunt hunger more than casein because it is faster digesting, providing a massive influx of amino acid to the blood stream very quickly. Taking branched-chain amino acids that are high in the amino acid leucine has also been found to dull hunger and limit additional food intake.
To read more about how protein, carbs, and fat influence body composition and food cravings, check out Avoid the Fat Trap
Fromentin, G., Darcel, N., et al. Peripheral and Central Mechanisms Involved in the Control of Food Intake by Dietary Amino Acids and Proteins. Nutrition Research Reviews. 2012. Published Ahead of Print.