New to losing weight, or starting over? This section covers the fundamentals that every plan, app and program relies on, explained plainly and backed by public-health guidance.
How weight loss works
Your weight changes when the energy you take in from food and drink differs from the energy your body uses over time. Eating a bit less than you burn, a calorie deficit, is the common thread behind every diet that works. What differs between approaches is how easy they make that deficit to sustain for you.
How fast is realistic?
The CDC notes that people who lose weight gradually, about 1 to 2 pounds a week, are more likely to keep it off. Expect faster loss in the first couple of weeks (partly water) and slower loss later as your body needs less energy. A 5% loss is already linked with health benefits for many people.
The three habits that matter most
- A modest calorie deficit you can live with. Not a crash diet.
- Enough protein and fiber to stay full and protect muscle. See our nutrition guides.
- Regular movement, especially walking and strength training. See our exercise guides.
Tools to get started
Estimate your numbers with our free calorie deficit calculator and BMI calculator. Both run in your browser and store nothing.
Guides in this section
- How Many Calories Should You Eat to Lose Weight?Estimate maintenance, choose a safe deficit and adjust as you go.
- Weight Loss Plateau: Why It Happens and What to DoTell a real plateau from water weight, then fix it step by step.