What If I Lose Weight Too Quickly?

A lot of people trying to lose weight often start out fast – dropping pounds at a rapid pace. But losing weight too fast can be detrimental to your health and sabotage your overall goals. Rapid weight loss is often followed by rapid weight gain. Or worse: Rapid weight loss can put your health at risk.

Research shows that rapid weight loss is rarely sustainable over the long haul. When you lose too much body fat in a short duration of time, your metabolism slows down as your body goes into high alert survival mode. It holds onto fat stores, the nutrients it needs from the foods you eat, and slows down the calorie-burning process.

In a 2020 review of weight-loss studies, people whose weight loss was more gradual had greater reductions in fat mass and body fat percentage than those who lost weight more quickly. They also maintained their metabolism better. An earlier study found that gradual weight loss was more favorable to body composition than rapid weight loss.

Your body also starts to battle your accelerated weight-loss efforts by increasing the release of hunger hormones, making you crave food.

Although you should always talk to your primary care provider before trying to lose weight, experts generally recommend you aim to lose just 1 to 2 pounds per week, depending on your gender, age and activity level. That will make your weight management effort more sustainable ongoing and help avoid harm to your health.

Losing weight rapidly can impact more than fat. It can mean you’re also losing muscle mass. Muscle mass is important for sustained weight loss.

For healthy muscle strength, bone density, energy and immunity, our bodies need certain amounts of fat, carbs, protein, minerals and vitamins. Rapid weight loss from dieting can also mean we’re not getting the right nutrition.  

Slashing calories can also cause fatigue, memory loss, irritability, dizziness and digestive problems such as diarrhea and constipation, and even hair loss.

Rapid weight loss can also lead to gallstones—the formation of hard material in the gallbladder. Your gallbladder’s job is to release digestive juices that break down foods and maximize the nutrients and energy they provide. When you quickly decrease your food intake, your gallbladder takes a vacation, releasing significantly fewer digestive juices that start to back up, sit in your gallbladder and create the hardened masses commonly called stones.