Fast Versus Slow Weight Loss: Which Is Better?

You’ve likely heard that when it comes to weight loss, slow and steady is the way to go. That’s because most responsible diet pros advocate for consistency over perfection or the idea that improving your eating and exercise over time is better than doing a complete overhaul you can’t sustain.

However, slow weight loss — usually defined by the range of 0.5–2 pounds (0.2–1 kg) per week — isn’t always the best option for long-term success. Here’s why experts say fast weight loss can sometimes be appropriate and how to tell which approach is best for you.

To lose weight, your “energy in” has to be lower than your “energy out,” a concept also known as energy balance. In other words, you have to maintain a caloric deficit to shed pounds. Generally, the bigger the deficit, the faster it happens.

You may have heard about the research showing people who lose weight rapidly are more likely to gain it back. When we lose weight, our metabolism adapts downward, meaning that once weight loss is over, we have to continue eating less food than before in order to maintain our new weight. That’s one of the biggest reasons dietitians tend to recommend a less rapid approach — so you can gradually adjust to your new “normal” rather than going all out and not being able to sustain it.

However, “the more recent body of research shows losing more than 2 pounds (1 kg) per week is still sustainable for certain people,” says Amanda A. Kostro Miller, RD. Of course, this won’t apply to everyone, but there are several reasons some people who lose weight quickly are able keep it off long-term.

“Weight loss of more than 2 pounds (1 kg) per week may indicate people have made really effective changes to their diet and exercise regimen,” says Kostro Miller. More importantly, the key in those cases is keeping up those healthy habits in the months and years to come.

Also, fast weight loss can be a great motivator to keep going, Kostro Miller points out. “Many people give up prematurely in their weight loss plan because they don’t see results fast enough.” But if a person sees their efforts are working, they may be more likely to stick with it.

Moreover, some research shows rapid weight loss can help improve LDL or “bad” cholesterol, insulin sensitivity, fasting blood sugar and insulin resistance more significantly than slower weight loss, notes Kostro Miller. These positive changes to overall health may make it easier to maintain weight loss.

“There are also times when a person needs a life-saving surgery and weight loss is required to safely perform the surgery,” explains Judith Scharman Draughon, RD. Other times a person’s weight is life-threatening on its own. “In these situations, whatever expedites fast weight loss — under a doctor’s care — is the best method.”

But even if you’re losing weight quickly and it’s working for you, sustainability is key. “It’s important to find a weight-loss program that works for you now and that can work for the rest of your life,” says Kostro Miller.

On the flip side, fast weight loss may be successful in the beginning, but it may not stand the test of time, says Kostro Miller. “People may initially lose a lot of weight fast, but experience burnout.” The changes they made, like putting certain foods or food groups off-limits and exercising more than usual may not be possible to maintain. Often, people find a smaller calorie deficit easier to accomplish day-to-day and stick with over time.

Fast weight loss can also make a person lose more muscle and body water than slower weight loss. “This indicates that slow weight loss can perhaps help you maintain more muscle mass. It’s important to preserve lean muscle mass as we age,” Kostro Miller notes. Not only is muscle more metabolically active than fat, which means it ensures your metabolism can put more calories to work, but muscle also tends to be harder to gain and maintain as we get older. So preserving what you have is important, particularly if you don’t have much muscle to begin with.

Whether you started off by losing weight quickly and want to slow down, or are struggling to maintain rapid weight loss, you can use these strategies to avoid yo-yoing and set yourself up for long-term success.

• Relax your calorie restrictions. “You may have restricted lots of food groups or greatly restricted calories before,” Kostro Miller says. But too many restrictions tend to make people miserable, and most people can’t “avoid carbs” for their entire lives. “Maybe instead of forgoing sweets, you allow yourself to have one or two desserts per week,” she suggests. “Try to avoid major restrictions, because once you feel too deprived for too long, you may be at risk of falling off the wagon completely and bingeing on your ‘off-limits’ items.
• Scale back exercise. If you’re exercising more than you can maintain, it could be helpful to ease up on your workout schedule. “Maybe instead of working out daily, you cut back to five workouts per week,” Kostro Miller recommends. “Or, you can decrease the amount of time that you work out at each session.” This way, you can avoid injury and burnout.
• Focus on adding rather than subtracting. A change in thinking can make weight loss and maintenance feel easier, regardless of your approach. “Instead of thinking about what you have to take out of your diet, think about all the healthy food you can add,” suggests Kostro Miller. “Fill your meals with fiber-rich fruits and veggies and you’ll feel fuller with less room for unhealthier foods.”

If you’re considering a rapid approach: “Take a step back and consider where you want to be in a year or even six months from now,” says Claire Virga, RD. “Do you want to have to continue eating fewer and fewer calories to maintain your weight?” If the answer is no, a slower approach may be better for you.

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