Here's one more reason to cut down on your red meat intake before all those Labor Day barbecues: High levels of iron consumption—like the super dose you get with a serving of steak—can lead to over eating and increased appetite later in the day, reports a new study from Wake Forest Baptist Medical Center in North Carolina. (Nix the problem with these 5 Ways to Feel Full Eating Less.)
Researchers looked at mice who were fed high-iron diets (equivalent to heavy red meat consumption) and found they had lower levels of leptin, a hormone that suppresses appetite and regulates metabolism. Without proper levels of leptin, you're likely to eat more food throughout the day, which is obviously a recipe for diet disaster. What gives? Fat tissue controls the release of leptin, but it adjusts its regulation of the hormone based on the amount of iron available. Higher levels of iron keep the tissue from signaling the body that you're full.
"The recommended daily allowance, or amount necessary to meet requirements of healthy individuals, is about 18 milligrams for adult females," says Lisa Moskovitz, a New York-based registered dietitian. Getting more than 25mg can lead to gastric upset, nausea, faintness, and interfere with your body's zinc absorption, she adds. (However, getting too little can have adverse effects too. Are Iron Supplements the Kick Your Workout Needs?)
But it's not just about banishing burgers. Even some of our favorite healthy staples—like dark leafy greens, beans, and soy—are rich sources of iron, so if your diet happens to be rich in the vegetarian sources, you could still be getting too much. (One cup each of soybeans, lentils, and spinach already puts you over Mostovitz' recommended amount.) Plus, a lot of multi-vitamins are fortified with iron.
"The key is to have to a balanced diet, including plenty of plant-based foods as well as lean protein sources," says Moskovitz. "Avoid eating large quantities of red meat only for the reason that it can take the place of other nutrient-dense healthy plant foods like fruits, veggies, whole grains, and legumes."
Iron is an important nutrient and shouldn't be avoided, but if you have a diet that's already packed with iron-rich foods, make sure you're not running the risk of falling into that high-iron, high-hunger group. Luckily, a six-ounce steak is only about 6mg of iron, so you'd basically have to be iron-loading breakfast, lunch, and dinner to risk the increased hunger and potential increased weight gain.
But still, back slowly away from that second burger at the barbecue—or whip up one of these Crazy-Good Burger Recipes for a Vegetarian Cookout instead.