How Fast Should You Lose Weight?

The short version

• 1 to 2 pounds a week is the standard guidance. For many people, 0.5 to 1% of body weight a week is a good range.
• Losing just 5% of your weight can noticeably improve blood pressure, cholesterol and blood sugar.
• The first couple of weeks are usually faster because much of the early loss is water.
• Fast loss doesn't guarantee faster regain, but very low-calorie diets carry real risks and need medical supervision.

The usual guidance

Public health agencies generally point to 1 to 2 pounds a week. That range works well for many people, but it isn't scaled to size: 2 pounds is very different at 150 pounds than at 300.

A more personal range is 0.5 to 1% of your body weight per week:

Faster at first and slower later is normal. Your first week or two can show a surprising drop because you're shedding stored carbohydrate and the water that goes with it.

What a realistic timeline looks like

If you have 40 pounds to lose, expect something closer to a year than to three months, including slow patches and weeks when life gets in the way. Most people's lowest weight comes after about 6 to 12 months of a structured effort, and then the job turns to keeping it off.

You may need to lose less than you think

Big goals can make a smaller, very worthwhile result feel like failure. But the health benefits start early:

• 5% of your body weight (10 pounds at 200 pounds) can improve blood pressure, cholesterol and blood sugar.
• About 7%, combined with regular activity, cut the risk of developing type 2 diabetes by 58% in people at high risk, in the landmark Diabetes Prevention Program.
• 10% or more tends to bring larger gains, including for fatty liver, joint pain and sleep apnea.

Consider setting your first goal at 5%. When you hit it, set the next one.

Is losing fast bad?

It depends how you do it. The CDC says people who lose weight gradually are more likely to keep it off, and a steady pace is certainly easier to live with. But fast loss doesn't automatically mean fast regain. In one randomized trial, people who lost weight quickly on a very low-calorie program regained about the same share of it, roughly 70% after about three years, as people who lost it gradually.

What makes rapid loss risky is what it usually involves. Diets under about 800 calories a day raise the risk of gallstones, muscle loss and nutrient shortfalls, and they're meant to be done under medical supervision. An extreme diet you do alone from the internet is a very different thing from a monitored clinical program. See crash diets and detoxes.

Signs you're going too fast

• You're losing more than about 1% of your body weight per week after the first few weeks.
• You feel dizzy, constantly cold or exhausted, or your workouts are falling apart.
• Your hair is shedding, your periods have stopped, or you can't sleep.
• You can't stop thinking about food, or you've started bingeing.

Sources

1. CDC: Steps for Losing Weight
2. Purcell et al., Lancet Diabetes & Endocrinology (2014): Effect of rate of weight loss on long-term management
3. Diabetes Prevention Program, NEJM (2002): Reduction in type 2 diabetes with lifestyle change
4. NIDDK: Dieting and Gallstones

This guide is general information, not medical advice. Please check with a clinician before making big changes, especially if you have a health condition, take medication, or are pregnant. Read the full disclaimer.