Whether you want to slim down for a big event (hello, wedding) or to quickly fit into your old jeans, the desire for fast weight loss is understandable. While fad diets can be tempting with wild promises (like, lose 20 pounds in one month!), they also tend to backfire and can wreak havoc on your metabolism. Most dieters who follow strict diets rebound and regain the weight.
Safe and sustainable weight loss, on the other hand, involves a lifestyle change and takes time: “Most of the research supports losing weight at a slow-and-steady pace to maintain the weight loss in the long-term,” confirms Ryan Maciel, RD, a certified strength and conditioning specialist based in Cambridge, Massachusetts.
Still, if you’re wondering exactly how much weight you can safely lose in one month, here’s your guide, according to weight-loss experts:
HOW MUCH WEIGHT CAN YOU LOSE IN ONE MONTH?
Weight loss depends on a myriad of factors, like age, gender, physical activity level and the effects of certain medications, so everyone goes at their own pace. A good rule of thumb is to aim to lose 1–2 pounds per week or 4–8 pounds per month, says Dr. Elizabeth Lowden, a bariatric endocrinologist at Northwestern Medicine Metabolic Health and Surgical Weight Loss Center at Delnor Hospital in Chicago. In other words, that’s about 5–10% of your body weight.
If you want to lose a pound a week, you’ll need a calorie deficit (aka less calories in comparison to those you need to maintain your current weight) of about 3,500 calories, or 500 calories per day, explains Lowden. Because it can be difficult to decrease your intake by that much, upping your physical activity can help burn more calories.
Keep in mind, though, week 1 of your weight-loss plan may be misleading. “It wouldn’t be uncommon to lose 5 pounds your first week, maybe even up to 10, but this isn’t a rate you can expect to continue — and you may even notice no weight loss the next couple of weeks,” says Lowden. That’s because as you lower your caloric intake and begin making healthier eating choices, your glycogen stores (aka molecules made from the carbs you eat) drop, and since they’re attached to water molecules, you lose water weight with them, explains Lowden. “So don’t feel discouraged if you initially burn pounds fast then fall into a weight-loss slow down — this is normal.”
HOW MUCH WEIGHT LOSS IS TOO MUCH?
Many people wonder if it’s safe to lose 20 pounds in a month. “Unless you’re enrolled in a medically-supervised weight-loss program or you’ve just had bariatric surgery, it’s very uncommon to lose more than 10 pounds per month,” says Lowden. Remember, if you lose weight too quickly, your body fights back. Your metabolism slows down, your hormones shift to increase your cravings and appetite, and you even burn less fat, according to a review in the International Journal of Obesity. These changes could lead to disordered eating habits, warns Lowden.
What’s more, no matter how quickly you’re losing weight, you also lose a certain amount of lean muscle mass in the process (especially if you’re not working out to build muscle), and losing too much could deeply damage your metabolism. That’s why strength training when trying to lose weight is important. Plus, a diet too low in calories could result in nutritional deficiencies, and rapid weight loss could lead to gallstones from improper gallbladder functioning, adds Maciel.
In short, a speedy weight-loss regimen to drop a dress or pants size is generally not worth it. As frustrating as it may be, try to be patient so you are successful long-term.
TACTICS FOR LOSING WEIGHT SAFELY
SET YOURSELF UP FOR SUCCESS
“It’s essential to have realistic goals and expectations before setting out on your weight-loss journey,” says Maciel. Tracking your weight-loss goals with an app like MyFitnessPal can be very helpful, he adds. Then, carve out time each week to plan your meals and workouts. After you’ve built up your confidence by reaching a few small goals, you can begin to aim higher with bigger challenges. For example, start by getting into a regular walking habit before training for your first 5K.
PREPARE FOR SETBACKS
Of course, progress is anything but linear — there will be times when you’ll hit a weight-loss plateau or even gain a few pounds back, despite your best efforts. But knowing and accepting this is part of the journey helps you stay on track, says Maciel. “While the number on the scale might take time to change, remember to acknowledge and celebrate how your clothes fit differently and how you’re able to lift heavier weights or jog longer,” suggests Lowden. These are all signs you’re on the right track.
FOCUS ON THE BASICS
“Don’t give up on the fundamentals of weight loss in search of the magic bullet,” says Maciel. It’s important to keep in mind that eating more nutrient-dense whole foods, exercising regularly, getting quality sleep and making time for self-care are all essential parts of the weight-loss equation. If you’re not losing weight on your current plan, take a hard look at your eating, exercise and lifestyle habits and consider reaching out for help from a support group or nutritionist, he suggests.
LISTEN TO YOUR BODY
When you’re working on eating and lifestyle changes, “there’s a normal amount of hunger that comes with reducing your intake, but you should never feel obsessively hungry,” says Lowden. “Honor your hunger cues with healthier choices.” To avoid overeating, mindful eating techniques can also help.
THE BOTTOM LINE
While healthy weight loss requires a lot of perseverance and dedication, the slow-and-steady route is your best bet. “So many people stop what they’re doing because they’re not seeing immediate changes, but consistency is key. You will note weight changes over time, but you have to stick with it,” says Lowden.
Originally published June 2019, updated with additional information
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