Browse the evidence

Intermittent Energy Restriction (including Intermittent Fasting and Time-Restricted Feeding) produces similar short- and long-term weight loss to continuous daily energy restriction when total caloric intake is equal.

If you struggle with daily calorie counting, try Intermittent Fasting (like 16:8 or 5:2). It works just as well as eating fewer calories every day, as long as you don't overeat on your 'off' days. Choose the schedule that fits your lifestyle best.

Long-term combined diet and exercise interventions produce significantly greater reductions in body weight, fat mass, and cardiovascular risk factors than either diet or exercise alone.

To lose the most weight and improve heart health over the long term (1+ years), you must combine dietary changes with physical activity. Do not rely on exercise alone; diet is actually more effective for weight loss than exercise by itself. However, adding exercise to your diet gives you the best possible results for both your waistline and your blood pressure/lipids. Aim for a sustainable caloric deficit and regular moderate-to-vigorous activity (aerobic and resistance) for at least a year.

An 8-week Very Low Carbohydrate Diet (VLCD) in older adults with obesity promotes significantly greater loss of visceral adipose tissue (VAT) and intermuscular adipose tissue (IMAT) compared to a standard low-fat diet, while preserving skeletal muscle mass.

If you are an older adult with obesity, switching to a very low-carbohydrate diet (less than 10% of calories from carbs) for 8 weeks can help you lose visceral and intermuscular fat much faster than a standard low-fat diet, without losing your actual muscle mass. You don't need to count calories strictly; simply prioritizing fats and proteins while keeping carbs very low tends to naturally reduce calorie intake and improve insulin sensitivity.

A Very Low Carbohydrate Diet improves insulin sensitivity and favorable lipid profiles (increased HDL, decreased triglycerides) in older adults with obesity compared to a low-fat diet.

Beyond just weight loss, switching to a very low-carbohydrate diet can significantly improve your blood markers for heart health, specifically by lowering triglycerides and raising HDL cholesterol, more so than a standard low-fat diet would.

Tirzepatide (5 mg, 10 mg, and 15 mg) significantly reduces body weight in patients with type 2 diabetes and obesity compared to placebo, GLP-1 receptor agonists, and basal insulin.

Tirzepatide is a highly effective treatment for weight loss in people with T2DM or obesity, outperforming other common medications like GLP-1 agonists and insulin. It is taken as a once-weekly injection. While it causes gastrointestinal side effects like nausea and diarrhea, these are usually mild and temporary. If you are considering this, discuss the benefits of significant weight loss against the potential for temporary stomach issues with your doctor.

In overweight/obese adults, a low-carbohydrate diet (26% of calories) without calorie restriction produces significantly greater weight loss and BMI reduction than a calorie-restricted diet (1200-1500 kcal) with standard carbohydrate intake (55-65%).

If you are overweight or obese, try reducing your carbohydrate intake to about 26% of your total calories (roughly 50-60g of carbs per day for many adults) without worrying about counting calories. Eat more fat and protein. You do not need to restrict your total energy intake to lose weight effectively; in fact, you may eat more calories than on a standard low-calorie diet and still lose more weight. This approach was shown to be superior to standard calorie restriction over 12 weeks.

Combining low-carbohydrate intake (26% of calories) with calorie restriction (1200-1500 kcal) yields the greatest reduction in BMI, body weight, waist circumference, and body fat compared to either intervention alone.

For the fastest and most comprehensive weight loss, combine a low-carbohydrate diet (26% of calories from carbs) with a moderate calorie restriction (1200-1500 kcal/day). This dual approach was shown to reduce BMI, body weight, waist circumference, and body fat more effectively than either strategy used alone. This is the most potent dietary intervention for overweight/obese individuals in this study.

For individuals performing resistance training, muscle strength increases linearly with total protein intake up to 1.5 g/kg body weight per day, with no additional benefit from higher intakes.

If you lift weights, aim for 1.5 grams of protein per kilogram of body weight daily. This is the sweet spot for maximizing strength gains. Eating more than this does not provide additional strength benefits.

Calorie restriction (energy deficit) is the primary driver of weight loss, with macronutrient composition having a secondary or negligible impact on long-term outcomes.

To lose weight, you must consume fewer calories than you burn. The specific type of diet (low-carb, low-fat, etc.) matters less for long-term success than maintaining that calorie deficit. Choose a dietary pattern you can sustain that creates this deficit.

Behavioral interventions (Cognitive Behavioral Therapy, Motivational Interviewing) are essential components of obesity treatment, as nutritional guidance alone is often insufficient.

Combine dietary changes with behavioral strategies like Cognitive Behavioral Therapy or Motivational Interviewing. These tools help build the skills necessary for long-term adherence to healthy habits.

In Thai adults with obesity and metabolic syndrome, a 12-week lifestyle education intervention combined with partial meal replacement (two meals daily) produces significantly greater weight loss and glycemic improvement than lifestyle education alone.

If you have obesity and metabolic syndrome, replacing two of your daily meals with a high-protein meal replacement shake, while also receiving basic lifestyle education on diet and exercise, will help you lose more weight and improve your blood sugar levels compared to just receiving lifestyle education alone. However, be aware that this benefit is most pronounced during the 12-week intervention period, and long-term maintenance requires ongoing support or continued use of the strategy.

A structured, task-based group weight management program (WAP) delivers significantly greater long-term weight loss and is more cost-effective than standard practice nurse-led advice in primary care for individuals in socially deprived areas.

If you live in a deprived area and struggle with weight, standard advice from your nurse might not be enough. Look for structured, group-based programs like the Weight Action Programme. These programs use weekly tasks, peer support, and self-monitoring to help you lose weight. They are designed to be delivered in local clinics, making them accessible. The key is consistency: attend the initial weekly sessions and then transition to monthly maintenance to keep the weight off.

In overweight and obese adults, low-carbohydrate diets (LCD) produce greater reductions in triglycerides, diastolic blood pressure, and body weight, along with greater increases in HDL cholesterol, compared to low-fat diets (LFD) over a duration of 6 to 23 months.

If you are overweight or obese, switching to a diet with less than 40% of your calories from carbohydrates (instead of less than 30% from fat) is likely to help you lose more weight, lower your triglycerides, raise your 'good' HDL cholesterol, and lower your diastolic blood pressure over the next 6-23 months. However, this benefit disappears after 24 months, where both diets are equally effective.

Reducing dietary energy density (consuming larger portions of lower-calorie foods) improves satiety and aids weight loss maintenance, regardless of total caloric intake in the short term.

To make your diet easier to stick to, choose foods that are less energy-dense. This means eating more vegetables, fruits, and lean proteins relative to fats and sugars. You can eat larger portions of these foods, which helps you feel fuller for longer, making it easier to maintain a calorie deficit without feeling deprived.

Subcutaneous Tirzepatide significantly reduces body weight, BMI, and waist circumference in adults with obesity or type 2 diabetes compared to placebo.

If you have obesity or type 2 diabetes and lifestyle changes haven't been enough, Tirzepatide is a highly effective, once-weekly injection that significantly reduces weight, BMI, and waist circumference. The effect is dose-dependent, with higher doses (up to 15mg) yielding greater weight loss. Be prepared for potential gastrointestinal side effects like nausea, which are common but often manageable.

In real-world clinical practice, tirzepatide produces significantly greater weight loss and higher rates of achieving clinically meaningful weight loss thresholds (≥5%, ≥10%, ≥15%) compared to semaglutide in adults with overweight or obesity.

If you are using tirzepatide (Mounjaro) or semaglutide (Ozempic) for weight loss, real-world data suggests that tirzepatide is more effective at helping you lose significant amounts of weight (10% or more of your body weight) compared to semaglutide. You are also more likely to reach these milestones faster with tirzepatide. However, both drugs carry similar risks of gastrointestinal side effects, so tolerability is a key factor in choosing between them.

Tirzepatide produces significantly greater weight loss than semaglutide in adults with obesity or overweight, with the magnitude of loss increasing with higher doses (>10 mg) and longer treatment durations (>6 months).

If you are using semaglutide and not achieving your weight loss goals, switching to tirzepatide (particularly at doses above 10 mg and continuing for more than 6 months) is likely to result in significantly greater weight loss. The data supports tirzepatide as a more potent option for reducing body weight compared to semaglutide.

Increasing physical activity (specifically total, light, and moderate-to-vigorous activity) or decreasing sedentary time during a dietary energy restriction intervention is associated with a faster rate of weight loss in women with overweight and obesity.

If you are on a calorie-restricted diet to lose weight, try to stay active or increase your daily movement. This paper shows that people who increased their physical activity (even light activity) or reduced their sitting time lost weight faster than those who became more sedentary. You don't need to start a rigorous gym routine; simply maintaining or slightly increasing your daily steps and reducing sedentary time can help you reach your goal sooner.

Increases in total and moderate-to-vigorous physical activity (MVPA) during the post-weight loss maintenance phase are associated with less weight regain (or greater weight loss) one year after the intervention.

After you reach your weight loss goal, don't stop moving. This study found that people who kept up or increased their moderate-to-vigorous exercise (like brisk walking or jogging) after losing weight were much more likely to keep it off one year later. Treat your post-goal activity as a permanent part of your lifestyle, not just a tool for getting to the goal.

A 3-month calorie-restricted ketogenic diet (KD) produces significantly greater weight loss than a calorie-restricted Mediterranean diet (MedDiet) in adults with obesity.

To lose more weight than a standard Mediterranean diet in 3 months, switch to a ketogenic diet with a 600-calorie daily deficit. This means eating very few carbs (5% of calories), moderate protein (30%), and high fat (65%). Ensure you are consuming enough calories to maintain basic function but below your maintenance level.

Modified Alternate-Day Fasting (mADF) produces significantly greater weight loss than a calorie-restricted Mediterranean diet (MedDiet) in adults with obesity.

Try modified alternate-day fasting: eat normally (but within your calorie limit) 4 days a week, and restrict calories to 400-800 on the other 3 days. This approach may yield better weight loss than a standard Mediterranean diet.

Late Time-Restricted Eating (lTRE) with an 8-hour window (2 pm - 10 pm) produces significantly greater weight loss than a calorie-restricted Mediterranean diet (MedDiet) in adults with obesity.

Try late time-restricted eating: restrict your eating to an 8-hour window from 2 pm to 10 pm. Ensure you are eating a balanced diet (45% carbs, 20% protein, 35% fat) with a 600-calorie daily deficit. This may yield better weight loss than a standard Mediterranean diet.

Weekly administration of semaglutide at 2.4 mg induces significant weight loss (mean 14.9%) and improves glycemic control (HbA1c < 7.0% in 57-74% of patients) in adults with obesity or type 2 diabetes, with effects proportional to dose and duration.

If you have obesity or type 2 diabetes, weekly semaglutide (2.4 mg for weight loss, 1-1.0 mg for diabetes) is a highly effective treatment that can lead to significant weight loss (up to 15%) and better blood sugar control. While nausea and vomiting are common side effects, they are usually mild and temporary, and weight loss often occurs regardless of whether you experience them. An oral version is also available if you prefer to avoid injections. Discuss this with your doctor to see if it's right for you.

Tirzepatide produces significantly greater weight loss than semaglutide in overweight and obese adults, with a standardized mean difference of 0.75 favoring tirzepatide.

If you are choosing between tirzepatide and semaglutide for weight loss, current direct comparative evidence suggests tirzepatide may lead to greater weight reduction. This benefit comes with a dual-hormone mechanism (GIP/GLP-1) and requires weekly injections. You should expect potential gastrointestinal side effects during dose increases, which are usually manageable. Combining the medication with diet and exercise will likely enhance results.