How Much Weight Can You Safely Lose in a Month?

Sure, you might be able to lose 15 or 20 pounds in a month, but that doesn't mean you should. We share the facts about safe and sustainable weight loss.

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Lots of people want to lose weight fast. Regardless of your weight loss goals or reasons, timing can feel like everything. So how much weight can you realistically lose in a month? Here's how to determine a safe amount of weight to lose in a month and ensure you're doing it healthfully. We're also sharing tips on losing weight in a safe, sustainable way.

How Much Weight Can You Lose in a Month?

That answer depends on the individual. Someone with a larger body can typically lose more because they have more weight to begin with.

"In general, 1 to 2 pounds per week, or 4 to 8 pounds per month, is a safe and sustainable amount to lose," says Sarah Gold Anzlovar, M.S., RDN, LDN and founder of Sarah Gold Nutrition. "Some people may lose more than that in the beginning, but it's often a lot of water weight and not true fat loss."

Weight fluctuations are more complex than calories in and calories out. Consider that 2 cups of water weigh about 1 pound, and most people lose weight just by going to the bathroom. Muscle, fat, bone, water, tissues, organs and whatever is inside your digestive tract make up your total weight. The number on the scale can't tell you if the weight you're losing is water, muscle or fat. Restrictive diets can help you lose weight fast, but you might be losing muscle and water weight, which is not ideal and can ultimately wreck your metabolism.

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Losing Weight Too Quickly Can Damage Your Metabolism

If you lose more than about 8 pounds in a month, not only will you likely not be able to keep it off, but it also means you probably engaged in unhealthy behaviors to get there. It's enticing to crash diet, but it may damage your metabolism in the long term. That, in turn, may negatively affect your ability to lose weight in the future.

Food is the body's main source of energy. If you aren't eating enough, your body has to find energy from somewhere else.

"Having a large calorie deficit often causes our bodies to break down muscle for energy, which can affect strength, athletic performance and metabolism," says Megan Ostler, M.S., RDN. The more muscle you lose, the fewer calories you burn, slowing your metabolism.

Anzlovar agrees, "Quick weight loss is typically not sustainable or healthy because it's usually achieved by severely restricting calories or overexercising, which can lead to binge eating, a slower metabolism and metabolic changes that encourage you to eat more and store more fat. Our bodies are really smart and want to protect us from starvation, which is what it detects if you are eating too few calories."

In other words, crash dieting—or attempting to lose 20 pounds in one month—leads to initial weight loss followed by gaining weight (and then some) after the diet is over.


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Tips for Sustainable Weight Loss

1. Focus On Small, Powerful Changes

Instead of crash dieting, work on changing your eating habits a few at a time. Also, consider your end goal for wanting to lose weight.

"It's important to consider why someone is interested in losing weight before we even get into how to do it. I prefer to advocate for healthy behaviors instead of making 'weight loss' the goal since people can be metabolically unhealthy in both small and large bodies," says Alyssa Ardolino, RD, nutrition communications coordinator at the International Food Information Council Foundation.

A lower body weight does not necessarily mean a healthier body. Ask yourself if you want to lose weight for health reasons, to look a certain way or because you liked how you felt at a certain number. Then, work with a professional, like a registered dietitian, to come up with a plan that's best for you based on your goals.

"While the diet industry will make it seem really simple, it's more than just eating less and exercising more. Weight loss also requires sleeping enough, reducing stress and staying hydrated," Anzlovar says. Small, sustainable choices win the weight-loss race, she emphasizes.

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2. Eat Nutritious Foods, Not Fewer

"Eat nutrient-dense foods most of the time, and limit the processed foods, sugary beverages and alcohol. This means filling your plate with fruits, vegetables, whole grains, beans, legumes, fish, poultry and small amounts of red meat, if you choose to eat meat, along with healthy fats like avocado, olive oil and nuts or seeds," Anzlovar says. "But don't completely restrict your favorite foods either. That will only lead to frustration and a later binge. Pair this with exercise you enjoy because otherwise, you won't stick with it."

Ostler echoes these recommendations. "When I work with people on weight loss, I like to start slow and focus on incorporating healthy nutrition behaviors instead of just a calorie deficit," she says. "For example, I have my clients focus on getting adequate protein at all meals, incorporating more fruits and vegetables, hydrating with water and limiting sweetened beverages, just to name a few. We start small to help incorporate lifelong habits instead of doing very low-calorie diets that often lead to rapid weight loss and then rebound weight gain as well as many physiological and physical effects of low-calorie dieting."

3. Adopt a Long-Term Mindset

Just because you weigh more in your 40s than in your 20s doesn't mean you are less healthy. While you want to avoid extreme weight losses and gains throughout your life, it is normal for weight to change over time. Focus on body composition—fat versus muscle—instead of the number on the scale. Fat and muscle weigh the same, but muscle takes up less space.

4. Stop Counting Calories

Rather than count calories, focus on hunger and satiety cues instead.

"Employ strategies of mindful and intuitive eating, such as practicing awareness at mealtimes and honoring your hunger cues," Ardolino says. "Aim to eat a diet full of variety and colors. Focus on healthy behaviors and how you feel before, during and after eating instead of focusing specifically on weight. If you've never consistently engaged in healthy behaviors before—maybe you've been yo-yo dieting for years, eating mindlessly or using food to cope with emotions—you'll likely lose some weight, but it's not guaranteed. But the peace that comes from removing anxiety and stress around eating is worth way more than the number on the scale."

The Bottom Line

While it's possible to drop a lot of weight in one month, we don't recommend it. Anything over 8 pounds is likely water weight that you'll gain back. Crash dieting leads to gaining more weight long-term and slows your metabolism.

Make small changes over time, like adding more vegetables, eating protein at every meal, cutting back on liquid calories from alcohol and sugary beverages, eating mindfully and exercising most days of the week. You'll feel better, and more importantly, you will stick to your healthy behaviors.

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