If you exercise a little, you can feel hungry. If you exercise a lot, you often feel less hungry. Scientists have discovered the “anti-hunger” molecule the body produces in response to exercise.
“We’re all generally aware that exercise is beneficial. It’s good for body weight and glucose control,” said Dr. Jonathan Long of Stanford Medicine, who led the research. “But we wanted to take a look at that concept in more detail — we wanted to see if we could dissect exercise in terms of molecules and pathways.”
Intense exercise causes the brain to release lac-phe, a hybrid of two chemical compounds, lactate and phenylalanine. This discovery could be key to making lac-phe-mimicking drugs that would cause the body to have the same reaction without the exercise. But, Dr. Long says there is a lot of research that needs to be done before we’ll reach that point.
However, while it’s a ways off, the potential is enormous. “We estimate that the lac-phe pathway is responsible for about 25% of the anti-obesity effects of exercise,” said Dr. Long.
When obese mice were given lac-phe, they weren’t as hungry and ate 30 percent less food. They lost fat, weight and had improved glucose tolerance. That’s mice, not people, but the fact that the same chemical appears in humans, mice and horses in response to exercise is promising.
“Regular exercise has been proven to help weight loss, regulate appetite and improve the metabolic profile, especially for people who are overweight and obese,” said co-corresponding author Dr. Yong Xu of Baylor College of Medicine. “If we can understand the mechanism by which exercise triggers these benefits, then we are closer to helping many people improve their health.”
Understanding how exercise impacts appetite is a huge step forward. Even if we don’t have a pill yet, we understand more about controlling hunger through working out. The researchers had healthy men exercise in three different ways. One time they cycled at a slow pace for 90 minutes, then they lifted weights, then they did 30-second “sprints” on bikes and lifted weights. While each type of exercise increased levels of lac-phe in the blood, the highest levels were seen after the most intense workout. So, if you want to lower your appetite through exercise, step up your activity.
The researchers point out that their findings make sense biologically. “If you’re sprinting from a rhino or some other threat, the autonomic nervous system yells at the brain to shut down digestion and any other unneeded processes,” said Dr. Long.
So, start sprinting from rhinos, metaphorically, to kickstart your weight loss goals.