Lowering your BMI comes down to reducing body fat through a combination of dietary changes, exercise, and lifestyle habits that you can sustain over months, not weeks. BMI is calculated from your height and weight, so the only way to change it is to change your weight. A healthy BMI falls between 18.5 and 24.9, overweight ranges from 25 to 29.9, and obesity starts at 30. The most reliable path to moving that number downward is a moderate calorie deficit paired with exercise that preserves your muscle mass.
Start With a Modest Calorie Deficit
Cutting roughly 500 calories per day from your current intake produces about one pound of weight loss per week. That pace, somewhere between 1 and 2 pounds weekly, is the range most strongly associated with keeping weight off long term. Losing faster than that tends to strip away muscle along with fat, which slows your metabolism and makes regain more likely.
A 500-calorie daily reduction sounds like a lot, but it adds up from small changes: swapping a sugary drink for water, reducing portion sizes at one meal, or cutting out a late-night snack. You don’t need to count every calorie precisely. The goal is a consistent, moderate gap between what you eat and what your body burns.
Prioritize Protein to Protect Muscle
When you eat less than your body needs, it pulls energy from both fat and muscle. Higher protein intake shifts that balance toward fat loss while sparing muscle. A 2024 meta-analysis found that eating more than 1.3 grams of protein per kilogram of body weight per day increased muscle mass during weight loss, while eating less than 1.0 gram per kilogram raised the risk of losing muscle. For a 180-pound person, that means aiming for at least 106 grams of protein daily.
Spreading protein across meals helps more than loading it all into dinner. Good sources include eggs, chicken, fish, Greek yogurt, beans, lentils, and tofu. If you’re significantly reducing calories, protein becomes even more important because your body is more aggressive about breaking down muscle when energy is scarce.
Combine Cardio and Strength Training
Exercise type matters more than most people realize. An eight-month trial comparing aerobic exercise, resistance training, and the combination of both in overweight and obese adults produced clear results. Aerobic exercise (walking, running, cycling) reduced total body weight and fat mass significantly more than resistance training alone. In fact, resistance training by itself did not reduce body fat or body weight at all in that study.
But the combination group got the best body composition outcome. People who did both cardio and strength training lost fat while also gaining lean muscle, which produced the greatest drop in body fat percentage. Resistance training alone increased lean mass but didn’t budge the scale. Cardio alone reduced weight but didn’t build muscle. Doing both gave people the benefits of each.
If your primary goal is lowering BMI, cardio should be your foundation. Adding two or three strength sessions per week on top of that protects your metabolism by maintaining the muscle that burns calories at rest. The combination does require more time, but it reshapes your body composition in ways that cardio alone cannot.
Sleep Enough to Keep Hunger in Check
Short sleep directly undermines weight loss by altering the hormones that control hunger. When researchers compared four hours of sleep to ten hours over just two nights, the short sleepers had lower levels of the hormone that signals fullness and higher levels of the hormone that drives hunger, even though both groups ate the same number of calories. Appetite and hunger ratings both increased significantly.
A larger study of over 1,000 people found the same pattern in real life: those sleeping five hours had measurably disrupted hunger hormones compared to those sleeping eight hours. Separately, the Quebec Family Study found that people sleeping only 5 to 6 hours were 69% more likely to be overweight or obese compared to those getting 7 to 8 hours. Poor sleep doesn’t just make you tired. It makes your body chemically hungrier.
Seven to eight hours appears to be the target range. If you’re doing everything right with food and exercise but consistently sleeping six hours or less, that gap alone can stall your progress.
Break Through a Weight Loss Plateau
Nearly everyone who loses weight hits a point, usually around 3 to 6 months in, where progress stalls despite no change in habits. This happens because your body adapts to lower calorie intake by slowing its metabolism and burning fewer calories at rest.
Several strategies help restart progress. Increasing protein to 1.2 to 1.5 grams per kilogram of body weight daily preserves lean mass and improves satiety. Eating more fiber-rich foods (vegetables, whole grains, legumes) slows digestion and helps you feel full on fewer calories. Increasing the duration, frequency, or intensity of your workouts gives your body a new stimulus to respond to. And small additions to your daily movement, like taking stairs, walking more, or using a standing desk, increase the calories you burn outside of formal exercise.
If you’ve lost significant weight and feel persistently fatigued, a short recovery phase where you eat slightly more for a few weeks can help. The temporary calorie increase reduces hunger, improves energy, and helps normalize the hormonal shifts that come with sustained dieting. This isn’t giving up. It’s a deliberate reset that can make the next phase of loss more sustainable.
When Medication Becomes an Option
For people with a BMI of 30 or higher, or a BMI of 27 or higher combined with a weight-related condition like type 2 diabetes, high blood pressure, high cholesterol, or sleep apnea, prescription weight loss medications may be appropriate. GLP-1 medications work by mimicking a gut hormone that reduces appetite and slows digestion. They’re not a replacement for dietary and exercise changes, but they can make those changes significantly easier to sustain for people whose biology is working against them.
BMI Isn’t the Whole Picture
BMI is useful as a screening tool, but it doesn’t distinguish between fat and muscle, and it says nothing about where your body stores fat. Waist circumference is a more direct measure of the visceral fat around your organs that drives cardiovascular risk. For women at a healthy BMI, a waist measurement of 80 cm (about 31.5 inches) or above signals increased risk. For men at a healthy BMI, the threshold is 90 cm (about 35.4 inches). These thresholds increase at higher BMI categories, but the principle holds: where you carry fat matters as much as how much you weigh.
As you work to lower your BMI, tracking your waist measurement alongside your weight gives you a more complete picture. Someone who starts strength training might see their BMI drop slowly while their waist shrinks faster, which reflects real improvements in health that BMI alone would understate.