This Is What Happens to Your Brain on a Diet

Your body and brain crave stasis and naturally work against losing weight. But that doesn't imply you can't diet healthily and sustainably. Here's what's going inside your brain when you fast.

There are many dieting tips, tricks, recipes, and meal plans available in a single Google search, all advancing different ways to lose weight. But beyond the hacks, what you consume and the amount you eat is altered by more than just your degree of motivation and the desire to look healthy. Moreover, if you’re on a diet plan meant to help you lose weight fast, sometimes it’s still a fight thanks to the natural urges of your body.

The first thing to know when you want to lose a few pounds is set to point weight. Actually, this is your body’s “happy weight,” including the amount of fat the body senses most comfortable carrying around. According to Dara Dirhan EdD, MPH, RDN, LDN, this amount of fat further becomes what the brain has determined to be the most suitable for optimal function.

“Two hunger hormones are liable for trying to regulate the body’s set point: ghrelin and leptin,” Dirhan reveals. Ghrelin is known as “the hunger hormone,” as it is secreted when the energy in the brain is weak. This hormone produces that hungry feeling that convinces you to consume glucose—your brain’s favored source for energy.

Leptin is known as the “satiety hormone” because it warns the brain when you’ve eaten enough, and energy levels are reached.

These signals have three primary roles, according to David Prologo, MD, a dual board-certified obesity-medicine physician, and interventional radiologist. They inform your body when to seek food when to slow down and save energy, and when to keep the fuel for a coming “hunger”—all in the name of survival.

“The brain is not concerned with looking slim and pretty,” Dr. Prolongo answers. “It is concerned with maintaining life.” Your body and the brain are programmed to remain stable at your set point.

Hence, when you first start a new diet—or you aren’t absorbing enough energy for your brain’s needs—you can feel symptoms like weakness, hunger, depression, fatigue, and headaches, amongst other symptoms. The good news is that after a few weeks, the brain eases up on these signals. Dr. Prologo explains that your body finds a new set point.

Dr. Jason McKeown, MD, Neurologist, and CEO of Modius Health add that once your body arrives at a new set point, you’ll specifically notice a reduction in your appetite and cravings.

“To maintain effects, diets in the long-term can affect this set-range, making your brain adapt and be satisfied at a lower weight,” Dr. McKeown says. Conversely, overeating some foods high in sugar and saturated fats in the long-run could change the set point for body fat upwards.

McKeown adds that altering how the brain works take months and sometimes even years, so diet and weight aims should be considered in the long-run.

“In the long-run, you could reset the weight span that your brain has established, which will make your body to speed up metabolism and reduce appetite, becoming comfortable with a lower weight,” McKeown states.

“In the short-run, you may lose a few pounds, but you will often plateau and see the weight creep back up as it is not enough to change the weight your brain and body is happy with.”

For brain health, Dirhan recommends choosing a whole-foods diet as much as possible. “This indicates that staying away from foods that have been processed or refined and including more low-energy-dense foods (foods lower in calories) into the diet, like fresh raw fruits and vegetables, lean meat, poultry, fish, and whole grains,” Dirhan states.

“Instead of concentrating on a ‘calorie salary,’ sticking to a whole-foods diet and practicing mindful eating is sure to make the brain happy while aiding in weight loss.” Concentrating on calories is just one of many things keeping you from losing weight.

Farrah Hauke, Psy.D., a psychologist in Scottsdale, Arizona, who practices in weight management and weight loss, recognizes and adds that we are more prone to binge when we are overly restricting what we consume. Plus, when we consume foods higher in fat or sugar, our brains deliver “feel-good” chemicals that make these experiences satisfying, Dr. Hauke says.

Specifically, when we consume “junk food,” dopamine neurons are stimulated. “We don’t view this same brain stimulation with ‘diet foods’ such as broccoli and grilled chicken breast,” Dr. Hauke answers.

The shortage of dopamine sparked by traditionally strict diets implies we are also less likely to find dieting reinforcing. Therefore, Dr. Hauke says we need to discover ways to reward ourselves, feel satisfied, and dodge “cognitive distortions”—negative thinking patterns that provide to the common all-or-nothing diet approach.

Dirhan, Dr. Hauke, Dr. McKeown, and Dr. Prolongo all agree that determined rules, unrealistic expectations about eating, and fancy diets aren’t the best strategies for your body and brain. Rather, focus on the quality of your diet, listening to your body’s craving cues, and adding in physical activity. Those, as mentioned earlier, along with these tiny changes, can help you lose weight.