We often expect weight loss to happen quickly. We believe that as soon as we make up our mind to cut back on snacking, the pounds should magically melt away after the first week.
“People make the decision that they want to start losing weight, and they want to see something in substantial numbers, so they go on a crazy diet,” says Kuldeep Singh, MD, the director of the Maryland Bariatric Center at Mercy in Baltimore. “But [any excess weight] is a concern that has been there for some time. It didn’t develop in a day, and it should not go away in a day.”
While we’d all love weight loss to be speedy, there are reasons the slow and steady approach is better, safer, and more effective.
Quick Weight Loss Is Less Effective
The best reason to pace yourself when it comes to weight loss is that it tends to be a more effective way to keep the pounds off. Fad or crash diets that promise fast results aren’t usually something the average dieter can sustain over months or years. Experts believe that as many as 95 percent of dieters regain weight.
If you’re trying to avoid the dreaded yo-yo dieting effect of regaining the weight you’ve shed (and maybe packing on more), taking it slow is a good idea. People who lose weight at a rate of about 1 to 2 pounds (lb) per week are more successful at maintaining their progress than those who lose at a faster rate.
This assertion is backed up by a systematic review and meta-analysis, which found that, even when the amount of weight loss was similar, dieters who lost the weight gradually as opposed to rapidly saw greater reductions in body fat percentage and fat mass. When rapid weight loss occurs, you’re far more likely to lose water weight, muscle, or even bone mass.
“Good weight loss is losing fat,” says Dr. Singh. “Bad weight loss is losing muscle.” You want to maintain your muscle mass for many reasons, but in a weight loss sense, muscle boosts metabolism by helping you burn more calories even when at rest. Singh adds that you’d likely need to be following a crash diet for a month or so for those health issues to take effect. Extreme forms of this are anorexia or bulimia, but milder forms are probably much more common than people think, he says.
Quick Weight Loss Can Be Dangerous
Plenty of fad diets promise rapid weight loss by eliminating foods or entire food groups, or drastically restricting calories, but in doing so, they also eliminate important sources of nutrition. Losing more than 2 lb a week over several weeks is considered rapid weight loss, and it is generally the result of eating too few calories. That practice is not usually recommended unless you’re under the supervision of a healthcare professional.
“It depends on what weight you’re starting at and your age, but people between 150 and 300 lb should not be losing more than 2 to 5 lb a week at any given time,” says Singh. “Anything more than that on a sustained basis is not healthy.”
Quick weight loss can put stress on the body and alter your hormonal response. The hunger hormones leptin and ghrelin, which tell your body when you’re full and when you’re hungry, respectively, can get out of sync, making you want to eat more often. If you drop 10 lb during the first week of a new diet, for example, it may seem like a huge success, but the weight loss will likely slow down, and you may even gain that weight right back once you stop or relax the diet.
Your metabolism may get out of whack as well. Your body adjusts to the lower calorie intake by slowing down the rate at which it burns calories, in an effort to guard against starvation. This is called “metabolic adaptation,” and it happens whenever you burn more calories than you take in. Once you go back to eating regularly, your body won’t know what to do with the extra calories, and that’s where weight gain sets back in. Linda Anegawa, MD, a Las Vegas–based double-board-certified physician in internal medicine and obesity medicine, and the founder of Pinnacle Metabolic Medicine, says that when you regain weight, you mostly regain fat.
Rapid weight loss can have other unhealthy side effects too. In addition to losing muscle mass, water, and bone density, it can introduce health issues such as gallstones, gout, fatigue, constipation, diarrhea, and nausea.
Losing weight too quickly may be especially dangerous for people with underlying health conditions, especially diabetes or kidney or stomach diseases, Singh says. Dr. Anegawa adds that if you shed a lot of weight, the appropriate dosage of your medications may change, so it’s important to work closely with a doctor to adjust your regimen.
The Best Approach for Lasting Weight Loss
A measured approach to weight loss will help you avoid potential health complications and raise the likelihood of long-term success at healthy weight maintenance. But what’s the best way to go about it?
Unlike short-term fad diets that make drastic changes, healthy weight loss usually involves implementing lifestyle changes that you can stick with far into the future. “Without sustainable lifestyle changes, you won’t be able to keep the health benefits of weight loss, plain and simple,” Anegawa says.
Healthy habits like eating a nutritious diet, moving often, managing stress, and sleeping well really can pay off over time, Singh says. “Those things are essential components of the weight loss picture,” he says.
These habits shouldn’t go out the window once your goal weight is achieved. By introducing habits you can stick with over time, a healthy lifestyle will become second nature, which will help you keep the weight off.
A systematic review of several weight loss registries identified the most successful strategies for weight loss and maintenance. These included making healthy foods available at home, eating breakfast regularly, eating more vegetables and fewer sugary and fatty foods, and increasing physical activity.
Don’t worry if you’re not seeing results quickly. “There’s nothing you’re going to gain out of short-term weight loss,” Singh says. Trying to do too much too quickly can be overwhelming. The key is to make small but permanent changes toward your goal. “You want to have a long, sustained weight loss program,” he says. “Take baby steps and enjoy those small goals that you achieve. Then set a new goal and move forward.”
The Takeaway
Most people who try fad diets or crash diets and lose weight quickly ultimately regain it.
A weight loss of more than 2 lb a week is considered rapid, and may lead to health risks.
The best way to lose weight safely is to develop healthy eating and lifestyle habits that can be sustained long-term.
Speak to a doctor if you’ve lost several pounds and may need to adjust a medication dose according to your new weight.
Sean Hashmi, MD, is an experienced nephrologist and obesity medicine specialist based in Southern California. As the regional director for clinical nutrition and weight management at a prominent healthcare organization in Southern California, Dr. Hashmi oversees the development and implementation of cutting-edge nutritional programs and weight management strategies. With his innovative approach and unwavering commitment to providing evidence-based solutions, he is a highly sought-after speaker and a leader in his field.
Hashmi founded the nonprofit organization SelfPrinciple.org to provide accessible and accurate health, nutrition, and wellness information to the public. Through this platform, he shares the latest research findings, empowering individuals to make informed decisions about their well-being. Self Principle also supports children's education by providing scholarships, books, and supplies, so that students have the resources necessary to succeed academically and build a brighter future.
Moira Lawler is a journalist who has spent more than a decade covering a range of health and lifestyle topics, including women's health, nutrition, fitness, mental health, and travel. She received a bachelor's degree from Northwestern University’s Medill School of Journalism and lives in the Chicago suburbs with her husband, two young children, and a giant brown labradoodle.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
Why People Diet, Lose Weight and Gain It All Back. Cleveland Clinic. October 1, 2019.
Ashtary-Larky D et al. Effects of gradual weight loss v. rapid weight loss on body composition and RMR: a systematic review and meta-analysis. The British Journal of Nutrition. June 24, 2020.
Is It Bad to Lose Weight Too Quickly? Cleveland Clinic. October 5, 2021.
Martins C et al. Metabolic adaptation is associated with a greater increase in appetite following weight loss: A longitudinal study. American Journal of Clinical Nutrition. October 19, 2023.
Paixão C et al. Successful weight loss maintenance: A systematic review of weight control registries. Obesity Reviews. February 12, 2020.
