If you’re clankin’ weights seven days a week and constantly fight a hunger only beef by the pound can satiate, take a step back. It’s likely all that red meat is making you hungrier, according to a study from Wake Forest Baptist Medical Center.
Sorry to break your Paleo-loving heart, but heavy dietary iron, equivalent to heavy red meat consumption suppresses a hormone called leptin that’s responsible for regulating your appetite. In the study, researchers fed mice high (2,000 mg/kg) and low-normal (35 mg/kg) iron diets for two months. At the end of the trial, the mice fed a high-iron diet had a 115 percent increase in the amount of iron in their fat tissue, and a 42 percent decrease in leptin levels in their blood compared to the mice fed the low or normal iron diet. Translation: it hurts your ability to detect fullness, despite all the food you're eating.
The researchers verified these figures from the animal model with ferritin blood tests (which measure the amount of iron stored in the body) from human participants involved in a previous clinical study. And, though they say they don’t know what an optimal iron tissue level is, they’re hoping to conduct large clinical trials since the study showed fat tissue responds to iron availability and adjusts leptin levels in the body, ultimately influencing appetite, energy expenditure, and metabolism.