Time to rethink your weight-loss meal plan.
You know that a protein-rich diet can help you feel fuller longer, but a recent study published in the journal Molecular Metabolism has narrowed down the best foods for triggering that “I’m full!” feeling—and potentially keeping you from overeating.
In the study, researchers at the University of Warwick set out to examine a specific set of cells in the brain called tanycytes that are located in the center of the brain region that controls body weight. What did they find? That, by detecting nutrients in the foods that you eat, tanycytes can actually trigger satiety, explains study author Nicholas Dale, Ph.D., a professor of neuroscience at the University of Warwick.
In the study, Dale’s team added concentrated amounts of the amino acids arginine and lysine into the brain cells of mice. Within 30 seconds, the tanycytes responded to the amino acids. “We don’t know yet if human tanycytes respond to the same types of amino acids that rodent ones do, but arginine and lysine are essential amino acids for humans as well as rodents, which would lead me to think it’s very likely this would also occur in humans,” Dale says.
Amino acids are the building blocks of protein, and arginine and lysine are critical for healthy muscles, bones, organs, and even hormone production.
“There’s loads and loads of evidence to show that elevated amino acids do diminish appetite and give you a feeling of satiety,” Dale says. “What we found was that, through the same taste detectors on the tongue that pick up that ‘umami’ flavor of amino acids, tanycytes can sense amino acids when they reach your blood and your brain, and send signals of fullness into the other parts of the brain that control appetite.”
The human body never makes lysine on its own, and it only sometimes produces arginine, which means you need to get them both primarily through the foods that you eat, explains Amy Gorin, R.D.N. They're both essential for optimum health and healthy weight loss.
What packs both arginine and lysine? Specific protein-rich, filling foods including pork shoulder, beef sirloin steak, chicken, mackerel, avocados, lentils, and nuts such as almonds, walnuts, and pistachios have the highest concentrations of these two amino acids, indicating that they’ll activate tanycytes—and trigger satiety—the fastest. Meanwhile, plums and apricots, which contain close to zero protein, are actually rich in arginine and lysine, too.
“One could imagine that instead of blindly going for a protein-rich diet, you could design a diet that is enriched in specific amino acids that are particularly good at activating tanycytes,” says Dale. The result: a fuller stomach and a healthier weight.
If you're looking to keep your eating habits in check, strategically add more arginine- and lysine-rich foods to your meals and snacks. Focus on incorporating one source of arginine and lysine to every meal, while making sure that every plate still has a source of whole carbs, protein, and healthy fat.
Remember, many arginine- and lysine-rich foods are also brimming with protein, fiber from whole carbs, and/or unsaturated fat. So one food might cross off a couple of food groups. For instance, mackerel is rich in arginine, lysine, protein, and healthy omega-3 fatty acids, Gorin explains. Lentils offer muscle-building protein along heart-healthy fiber from whole carbs. And almonds? Well, they've got it all going on: protein, fiber, and healthy fats. Avocados have that monounsaturated fat thing covered.
Mmm... some avocado toast with some chopped almonds sounds pretty good right about now.