After overhauling your diet, upping your exercise, managing your stress, and working hard to lose weight, you may feel like reaching your goal weight is like crossing the finish line: all the hard work is over and you can coast in your new body. Turns out losing weight is just half the battle — the real work comes in keeping it off.
Eduardo Grunvald, MD, program director at UC San Diego's Weight Management Program, told POPSUGAR that switching from weight-loss mode to weight-maintenance mode [1] requires more effort just to keep the weight off. "If you were at that higher weight for quite a while, your body is going to try to do things to sort of rebound the weight back," he said.
Your Metabolism Slows Down
One of those things is slowing down your metabolism. As you lose weight, your metabolism slows down to conserve energy stores, he explained. This process was identified during a Biggest Loser study [2] that was published in the journal Obesity in 2016. Researchers found that all but one of the 14 former contestants on the show regained the weight they lost; they also found season eight winner Danny Cahill's metabolism had slowed down significantly. Even when they gained the weight back, the contestants' metabolisms still stayed slowed down.
Although we're used to having food readily available, Dr. Grunvald explained that our genes are still the same genes as when humans lived in food scarcity and sometimes went days without food. When your body weight goes down, your metabolism slows down, too. "Essentially, our bodies kind of slow down metabolism to prevent starving to death," he said.
Your Hormones Change
"When you lose weight, a lot of your hormones shift so that it tells your brain to consume more calories," Dr. Grunvald explained. One of these hormones that gets out of whack is leptin [3], the satiating hormone that suppresses appetite. When you lose weight, your leptin levels drop, which means your body isn't readily signaling that it's full.
Not only does this make you hungrier, but it also changes the way you process food. "That doughnut tastes a lot better after weight loss than it did before," he said. "It's just the brain's way of getting you to consume more calories to regain that weight."
You Revert Back to Your Old Ways
In addition to the physical responses that happen when you lose weight, such as your metabolism slowing down and your hormones changing, your environment and behaviors can also trigger weight regain. If you revert back to how you lived before you lost the weight, you will inevitably slip back into old habits and gain the weight back. It's important to remember that even though you lost weight, your hard work isn't done; rather, maintaining weight loss requires vigilant effort.
In fact, you may have to work harder to maintain weight loss than you did when you initially lost it. When assessing the National Weight Control Registry [4], a database of people who have lost 30 or more pounds and kept it off for at least a year, researchers noticed that most of the patients exercised more during the maintenance phase than they did during weight loss. "It doesn't mean that you have to go to the gym two hours or you have to run a marathon," Dr. Grunvald said. "It just means that you walk an extra half hour, an extra hour a day just to maintain the weight."
How to Prevent Weight Regain
Knowing that it still takes a constant effort to maintain weight loss, you can arm yourself with the right tools to keep the weight off for good [5]. Dr. Grunvald said the most important factor is to have a positive environment and ongoing support system, whether that's a weight-loss program, dietitian, health educator, or obesity medicine doctor or clinic.
It also requires keeping up habits of tracking your food and weighing yourself, especially if you used those tools to lose the weight in the first place. He suggested planning your meals ahead of time, limiting the number of meals you eat out, and increasing physical activity to maintain weight loss.