It’s easy to understand why rapid weight loss is an appealing goal. Whether you have an upcoming event, like a wedding or a reunion, or you simply want to fit into a favorite outfit, quickly trimming down — such as by losing 10 pounds in three weeks — can sound like a winning strategy. But even though quick-fix diets may promise weight loss of over 3 pounds per week, experts say this isn’t usually safe or sustainable.
“Losing 10 pounds in three weeks is generally not recommended, as it is considered to be excessively rapid weight loss,” says Melissa Mitri, RDN, of Milford, Connecticut. Instead, health authorities like the National Heart, Lung, and Blood Institute and the Centers for Disease Control and Prevention (CDC) recommend a slower, steadier rate of about 1 to 2 pounds per week. Plus, weight loss is a highly individualized process that depends on a variety of factors (like age, health conditions, and your unique metabolism), so a safe and achievable rate of weight loss may look different for you than someone else.
Here’s what to know about losing the right amount of weight in a way that lasts.
How to Work Out a Safe Calorie Deficit
The key to safe, successful weight loss is setting (and maintaining) an appropriate calorie deficit. That means burning more calories than you take in, through a combination of diet and exercise.
So, how do you determine a calorie target that puts you consistently “in the black”? “To calculate the right amount for your needs, you need to first know your daily maintenance calorie needs,” says Mitri. She suggests using a simple formula like the Mifflin-St Jeor equation to determine that number.
Once you have the number, you can decide how many calories to cut. To hit the 1-to-2 pound-per-week weight loss mark, a deficit of at least 500 calories per day is generally necessary. “Some research shows a deficit of up to 700 calories per day may be needed to achieve weight loss, but a 500-calorie deficit is a solid starting point,” Mitri says. Since 1 pound of weight loss equates to 3,500 calories, dialing back by 500 per day could achieve this much in seven days.
With this in mind, the extremely challenging nature of losing 10 pounds in three weeks becomes much clearer. Losing 3.3 pounds per week would require a calorie deficit of about 1,600 calories per day.
1,600 x 7 days = 11,200 calories per week, or 3.2 pounds
That’s not safely attainable for many people. Unless you’re starting at a very high calorie intake, cutting out this many calories will likely reduce your food intake beyond a safe limit. A low-calorie diet typically allows for an intake of 1,200 to 1,500 calories for women and 1,500 to 1,800 calories for men.
Harvard Health Publishing strongly advises against consuming fewer than 1,200 calories for women or 1,500 calories for men without the supervision of a healthcare professional.
What are the Risks of Losing 10 Pounds in 3 Weeks?
Although losing 10 pounds in three weeks might seem like it can usher in the cosmetic results you’re after, it comes with significant risks. For starters, when you lose weight quickly, you’re more likely to regain it. You can only keep up a restrictive diet for so long before hunger overcomes willpower, says Lainey Younkin, RD, weight loss dietitian at Lainey Younkin Nutrition in Boston.
Meanwhile, under-eating for too long can backfire in several ways. “Cutting out too many calories leads to less energy, increased hunger, and muscle loss, which slows your metabolism,” Younkin says. A significant portion of the 10 pounds you may lose in three weeks could also be water, not fat, she adds.
Nutrient deficiencies can also develop during excessively fast weight loss. By dramatically cutting calories, you may miss out on some of the essential macronutrients, vitamins, and minerals you’d get from your regular diet. Mitri says that this can lead to electrolyte disturbances, increased risk of gallstones, and other health problems.
Besides the physical downsides of rapid weight loss, your mental health might also take a hit. “Rapid weight loss may have links to increased anxiety, depression, binge eating, and overall food obsessions, as the body and mind are in a sort of fight-or-flight mode,” Mitri says. Extreme calorie restriction can also trigger disordered eating thought patterns and behaviors, particularly in people who have experienced those issues previously.
How to Lose Weight Steadily and Sustainably
Weight loss is a unique journey for each person, and no perfect one-size-fits-all plan exists. But some practices can help you sustainably stay on course while losing 1 to 2 pounds per week, including the following:
Add exercise. Staying active not only helps burn calories but also prevents you from losing muscle mass as you lose weight. For general health, the CDC recommends taking part in at least 150 minutes per week of moderate-intensity aerobic activity, such as brisk walking, jogging, cycling, or swimming.However, you may need to add more activity than this to boost weight loss.
Focus on eating healthy. Rather than excessive calorie restriction, focus on eating whole foods, a balanced nutritional profile including plenty of protein and healthy fats, and plenty of plant-based foods in place of animal-sourced products. It can also help to limit foods that are high in added sodium and sugars.
Track your intake. Younkin says that even if you don’t count calories, tracking what you’re eating is helpful. To get a sense of how much you’re taking in each day, she suggests keeping a food journal or even taking photos of your meals.
Take the long view. “Slow, steady, sustainable weight loss requires embracing the long game, focusing on simple habit changes every day and constantly working on your mindset,” Younkin says.
Consult a professional. If you’re feeling stuck with your weight loss, a registered dietitian can tailor an eating plan to your specific needs and circumstances.
The Takeaway
Rapid weight loss, such as dropping 10 pounds in three weeks, may pose significant health risks, and healthcare professionals do not generally recommend it.
Attempting to reach extreme calorie deficits can result in nutrient deficiencies, slowed metabolism, and even gallstones.
Aim for a steady weight loss of 1 to 2 pounds per week by combining balanced eating and regular exercise, which healthcare professionals advise for safe, sustainable results.
A registered dietitian can provide personalized guidance that fits your unique situation and health needs, if you find weight loss to be challenging or feel that it would benefit your overall health.
EDITORIAL SOURCES
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.
Kara Andrew, RDN, LDN, is the director of health promotion for Memorial Hospital in Carthage, Illinois. She is also licensed as an exercise physiologist and certified in lifestyle medicine by the American College of Lifestyle Medicine. Her experience includes corporate wellness, teaching for the American College of Sports Medicine, sports nutrition, weight management, integrative medicine, oncology support, and dialysis.
She earned her master's in exercise and nutrition science at Lipscomb University.
Andrew has served as a president and board member of the Nashville Academy of Nutrition and Dietetics. She was recently elected a co-chair of the fitness and medicine group in the American College of Lifestyle Medicine.
Sarah Garone is a licensed nutritionist, registered nutrition and dietetics technician, freelance health and wellness writer, and food blogger in Mesa, Arizona. She has written for TheWashington Post, Healthline, Greatist, Verywell, and Eat This, Not That, among other outlets. She is a member of the Academy of Nutrition and Dietetics.
