If you’re on track to shed some serious pounds, you still need to watch your pace. (Insert inspirational ‘it’s a marathon, not a sprint’ quote here.) While it’s tempting to go all in, cut back on calories, and crank up your workouts, a hardcore approach to losing weight often leaves you stressed beyond belief and physically burnt out. And, dropping too many pounds too fast can actually backfire on your goals—and your health.
Do your grumbling tummy, your metabolism, and your waistline a favor: Read on to make sure your weight-loss pace is healthy and sustainable—and free yourself from the whiplash of ‘yo-yo dieting’ forever.
How Much Is Too Much?
The number of pounds you can safely lose per week depends on your body size—but for most people, losing more than one or two pounds a week is overdoing it, says Partha Nandi, M.D., F.A.C.P., leading physician and author of Ask Dr. Nandi.
“The more body fat you carry, the more you’ll be able to safely lose per week,” he says. Generally, you can lose about one percent of your total body weight per week, which is about a pound and a half per week for someone who weighs 150 pounds and two pounds a week for someone who weighs 200 pounds.
Crash Dieting 101
Losing more weight per week requires some extreme measures (like swearing off carbs and overdoing it at at the gym) that drive your willpower into the ground—and ultimately aren’t very healthy for your body, Nandi says.
Even when you’re doing it the healthy, slow-and-steady way, losing weight is a numbers game. To lose a pound a week, you need to create a 500-calorie daily deficit, according to Nandi. To bump that up to two pounds per week, you need a 1,000-calorie daily deficit.
In order to accomplish that, you need to consistently burn more calories in the gym and put less on your plate. So if you normally eat 2,000 calories a day, you’d need to cut 500 calories out of your grub and burn another 500 through exercise—every day.
That sounds tough enough as it is, right? To lose any more than that per week, you’d need to create a caloric daily deficit closer to 1,500 or 2,000 calories, which would likely require a dangerous combination of calorie restriction and over-exercising, Nandi says.
First of all, when you cut calories this hard, you end up missing out on the nutrients you need, he explains. But beyond falling short on important vitamins and minerals, you also don’t give your body the calories it needs to fuel your day, which becomes an even bigger problem if you’re cranking up your workouts, says LA-based celebrity trainer Astrid Swan.
Getting ample calories—and the carbs, fats, and protein they provide—is crucial for powering through and recovering from exercise. So if you try to go hard at the gym while on a very low-cal diet, chances are you’ll feel exhausted while you’re there, crazy sore afterwards, and possible even land yourself with an injury, she says.
And, ultimately, crash dieting wrecks your metabolism (which determines how many calories you need), backfiring on your weight-loss efforts, says Nandi. “Drastically cutting your calorie intake will slow your metabolism to a point where your calorie deficit is significantly smaller than what you planned it to be,” he explains. Basically when you give your body too few calories it adapts by slowing your metabolism down so you can survive on the calories you are getting. (Ever heard of ‘starvation mode’? Yeah, this is it.)
With that slower metabolism, your weight loss stalls—and you’ll put pounds back on as soon as you go back to your old ways. So begins the vicious cycle of “yo-yo dieting,” many people get trapped in, Nandi says.
Are You Digging Yourself Into A Calorie Deficit Hole?
If you’re losing weight too rapidly, your body will let you know. You’ll probably feel fatigued 24/7, and may notice a slew of digestive issues, like nausea, diarrhea, and constipation, says Nandi. You may also feel lightheaded and sick to your stomach when working out. These symptoms all indicate that your body is running on empty—and constipation in particular can signal that you’re not getting enough fiber or calories to keep things moving, Swan says.)
You may even have trouble sleeping and experience mood swings, according to Swan. Eating too little and exercising too much can affect your hormones and blood sugar, which then leave you tossing and turning at night and stressed out during the day. The stress on your body and the mental and emotional stress of depriving yourself and working so hard make for a slippery slope to feeling pretty terrible. In extreme cases, this stress can even make your hair fall out, says Swan.
Get Your Sanity—And Your Results—Back
First things first, make sure you’re getting enough calories to lose weight safely. “The average woman needs to eat about 2,000 calories per day to maintain weight, and 1,500 calories per day to lose one pound per week,” says Nandi. “The average man needs about 2,500 calories to maintain, and 2,000 to lose a pound a week.”
Nandi recommends meeting with a dietitian or doc to determine how many calories you need for your body size, lifestyle, and goals. From there, you’ll begin to add calories back into your diet to ensure your body gets the nutrients it needs to thrive.
You may also need to rethink your workout routine. If you’re not taking a rest day, make sure to add one, says Swan. “When I am working with clients, they are shocked to see that when they eat more calories (and the correct nutrients), and take a rest day, their results improve,” she says.
Focus your workouts on strength training, which builds muscle and supports your metabolism, and turn to HIIT for cardio, so you can reap extra benefits in less time, Swan recommends.
Related: 7 Natural Ways To Kickstart Your Metabolism