Browse the evidence

An intensive lifestyle intervention (ILI) comprising behavioral therapy, nutritional counseling, and physical activity produces significant weight loss (-11.3%) in morbidly obese patients, serving as an effective alternative to bariatric surgery for non-surgical candidates.

If you have morbid obesity and cannot or choose not to have surgery, an intensive lifestyle program focusing on behavioral changes, Mediterranean-style eating, and daily light exercise plus aerobic activity can lead to significant weight loss (over 11% on average) compared to standard medical care. Consistency is key, as the program requires frequent initial engagement.

Large-volume surgical removal of subcutaneous abdominal fat (liposuction) does not improve insulin sensitivity or cardiovascular risk factors in obese individuals, whereas caloric restriction (negative energy balance) rapidly improves metabolic health independent of significant fat loss.

Surgical removal of fat (liposuction) does not fix metabolic health or insulin resistance. To improve metabolic health, you must create a negative energy balance (eat less than you burn), which reduces fat in the liver and muscles, rather than just trying to reduce total body fat mass through surgery.

Decreasing dietary energy density (specifically solid food) predicts significant weight loss in obese adults over 18 months, primarily by reducing total energy intake without altering food volume.

To lose weight, focus on lowering the energy density of your solid foods rather than just eating smaller portions. This means choosing foods with more water and fiber relative to calories. You can keep your plate looking full and satisfying while significantly reducing your calorie intake, which leads to weight loss.

A very-low-calorie diet (VLCD, ≤800 kcal/day) produces significantly greater weight loss and more pronounced improvements in hyperandrogenemia (Free Androgen Index) and metabolic markers compared to a moderate energy deficit diet in obese women with PCOS over an 8-week period.

For obese women with PCOS seeking rapid hormonal and weight improvement, a medically supervised VLCD (800 kcal/day) for 8 weeks is significantly more effective than standard moderate dieting. It achieves nearly triple the weight loss and can induce biochemical remission of PCOS symptoms, which moderate dieting failed to do in this trial. This requires strict adherence to meal replacements and medical oversight.

Tirzepatide significantly reduces body weight, BMI, and waist circumference in overweight or obese adults without diabetes compared to placebo.

If you are overweight or obese and do not have diabetes, tirzepatide is a highly effective prescription medication for significant weight loss. It is taken once a week by injection. While it causes side effects like nausea and vomiting in many people, the weight loss benefits are substantial. You should discuss the risks and benefits with your doctor and start with a low dose to minimize side effects.

Lorcaserin (10 mg twice daily) produces significant weight loss and improves cardiometabolic risk factors in obese adults by selectively activating 5-HT2C receptors to reduce energy intake without increasing energy expenditure.

Take 10mg of Lorcaserin twice daily, ideally before breakfast and dinner, while following a lifestyle program that creates a moderate caloric deficit. This medication works by reducing your appetite through specific brain receptors, leading to significant weight loss and improved metabolic markers like blood pressure and cholesterol without increasing your energy expenditure.

Supplementation with the herbal blend LI85008F (900 mg/day) significantly reduces body weight, BMI, and visceral adiposity in healthy overweight adults compared to placebo when combined with modest caloric restriction and exercise.

Take 900mg of LI85008F daily (split into two 450mg doses) alongside a modest calorie-restricted diet (around 1800 kcal) and regular walking. This combination has been shown in a 16-week clinical trial to significantly reduce body weight and BMI in overweight adults compared to placebo.

An energy-reduced anti-inflammatory diet significantly improves hepatic status indices (NAFLD-FLS, FLI, FIB-4) and reduces inflammatory biomarkers in younger adults with obesity compared to a standard isocaloric diet.

To improve liver health and reduce inflammation, focus on an energy-reduced diet rich in anti-inflammatory foods like vegetables, fruits, whole grains, fish, and olive oil. This approach was shown to significantly improve liver fat scores and reduce inflammatory markers in adults with obesity over 6 months, outperforming a standard weight loss diet in some inflammatory markers.

Whey protein supplementation combined with resistance training significantly improves lean mass, fat mass, and muscular strength in healthy individuals, but fails to produce these benefits in individuals with pathological conditions.

If you are healthy and under 40, adding whey protein to your resistance training routine will likely help you gain lean mass and lose fat. However, if you are older or have a chronic health condition, whey protein alone during training may not provide these specific benefits, and you might need to look into multi-nutrient supplementation strategies instead.

Whey protein supplementation combined with resistance training significantly improves body composition (lean mass gain and fat mass loss) and muscular strength specifically in individuals under 40 years of age, but not in older individuals.

If you are under 40, whey protein after resistance training is a proven strategy to build muscle and lose fat. If you are over 40, this specific combination may not yield the same results, and you should consider discussing multi-nutrient options (like vitamin D and leucine-enriched whey) with a professional.

Intermittent fasting (IF) significantly reduces body weight, BMI, fat mass, and triglycerides compared to regular diet in overweight/obese adults aged 40+ without metabolic disease, without causing significant loss of lean body mass.

If you are over 40 and overweight, trying intermittent fasting (like time-restricted eating or alternate-day fasting) can help you lose fat and weight without losing muscle, compared to just eating normally. Stick to a 2-6 week trial to see if it works for you.

Intermittent fasting significantly reduces fat mass in overweight/obese adults aged 40+ without metabolic disease, with greater efficacy in those with lower BMI (overweight to mild obesity) and with Time-Restricted Eating (TRF) protocols.

If you use Time-Restricted Eating (TRF), you may see better weight loss results, especially if your BMI is under 32.5.

Lowering dietary energy density (ED) significantly reduces total energy intake in both children and adults without requiring portion size reduction.

To reduce calories without feeling hungry, focus on lowering the energy density of your meals. This means increasing the proportion of water-rich foods (like vegetables) and decreasing energy-dense components (like fats and sugars). You can eat the same amount of food by weight, or even more, while consuming significantly fewer calories.

Combining sibutramine (10-15 mg/day) with a low-calorie diet using meal replacements and behavioral modification significantly improves both weight loss and long-term weight maintenance compared to diet and behavioral modification alone.

To lose weight and keep it off, combine a prescription medication (sibutramine) with a structured low-calorie diet that includes meal replacement shakes and behavioral counseling. This combination was significantly more effective than diet and counseling alone in maintaining weight loss over 12 months.

Time-restricted eating (TRE) with an 8-hour or shorter eating window significantly reduces body fat percentage, fat mass, lean mass, body mass, BMI, and waist circumference in adults with overweight and obesity compared to control groups.

If you are overweight or obese, try limiting your daily eating window to 8 hours or less (e.g., eating only between 12 PM and 8 PM). This approach has been shown to significantly reduce body fat, waist size, and overall weight compared to unrestricted eating. While you may lose some lean muscle mass, the overall health benefits for fat loss are significant. If you prefer a 10-12 hour window, you may not see the same level of fat loss.

A comprehensive, blended-learning lifestyle intervention (Individual Health Management) produces significantly greater weight loss and metabolic improvements than standard written advice in overweight/obese adults over 12 months.

To lose significant weight, you need more than just a pamphlet. Engage in a structured program that combines education, regular coaching, and self-monitoring tools. Choose a dietary approach (fasting, calorie counting, or meal replacements) that you can stick to, and use technology to track your progress. Consistency over 12 months is key to maintaining the loss.

Orlistat (360 mg/day) produces significantly greater total body weight loss and fat mass reduction than metformin (1000 mg/day) in obese premenopausal women over 3 months.

If you are an obese premenopausal woman looking to lose weight, orlistat (360mg/day) combined with a balanced diet is likely to produce significantly greater weight loss than metformin (1000mg/day) over a 3-month period. Be prepared for potential gastrointestinal side effects, which are usually mild.

Combining a reduced-calorie diet (1,500 ± 200 kcal) with moderate aerobic exercise produces significantly greater reductions in BMI, waist circumference, and body fat percentage compared to diet alone in overweight/obese women.

To lose fat and improve body composition, do not rely on diet alone. Combine a moderate caloric deficit (around 1,500 kcal) with regular moderate exercise (like brisk walking or cycling for 30+ minutes, 3-5 times a week). This combination is significantly more effective for reducing body fat and waist size than dieting by itself.

Energy-restricted dietary interventions (specifically very-low-calorie diets of 600-853 kcal/day) can induce remission of type 2 diabetes (HbA1c <6.5% without medication), with remission rates strongly correlated with the magnitude of weight loss and inversely correlated with the duration of diabetes.

If you have recently been diagnosed with Type 2 diabetes, aggressive calorie restriction (often via meal replacements around 600-850 kcal/day for a few months) under medical supervision can potentially put your diabetes into remission. The key factors are losing a significant amount of weight (often >10% of body weight) and acting early in the diagnosis. This is not just about weight loss for aesthetics, but a medical intervention to restore metabolic health.

Moderate caloric restriction (approx. 3% body weight loss) significantly improves insulin sensitivity (measured by HOMA-IR, QUICKI, and Matsuda index) in middle-aged obese pre-menopausal women, despite not improving early-phase beta-cell function.

For obese women, aiming for a modest 3% body weight loss through a moderate caloric deficit (around 1,200 kcal/day) for 12 weeks can significantly improve insulin sensitivity. This metabolic benefit occurs even if early-stage beta-cell function doesn't improve, suggesting that moderate lifestyle changes are effective for preventing type 2 diabetes in this demographic.

Very Low-Energy Diets (VLEDs), defined as 1700–3330 kJ/day, produce rapid and significant short-term weight loss (9–26 kg over 4–20 weeks) in adults with obesity (BMI ≥ 30 kg/m²), though long-term maintenance is variable and often requires behavioral or pharmacological support.

If you have a BMI over 30, a Very Low-Energy Diet (VLED) is a clinically supervised, severe restriction of calories (400-800 kcal/day) typically using meal replacements. It works fast, shedding 9-26 kg in a few months. However, keeping the weight off is hard without adding behavioral support or medication, and you must transition carefully to regular food to avoid regaining it.

Initiating supervised exercise immediately at the start of a weight loss program (0-3 months) yields significantly greater weight loss and waist circumference reduction compared to delaying exercise until 6-9 months, with benefits persisting at 24 months.

If you are starting a weight loss journey, begin supervised exercise immediately, not after you have lost some weight. This study shows that starting circuit training (light weights, high heart rate) within the first 3 months leads to significantly more weight loss and waist reduction than starting it later. The early exercise acts as a motivator to keep you on track.

Intensive Lifestyle Intervention (ILI) consisting of behavioral therapy, nutritional counseling, and supervised exercise induces significant weight loss in morbidly obese patients (BMI >40) without calorie restriction, outperforming conventional obesity therapy.

For morbidly obese individuals, a structured, intensive lifestyle program focusing on behavioral changes, Mediterranean diet principles, and gradual exercise progression can achieve significant weight loss (approx. 11%) without strict calorie counting. This approach is superior to standard medical care alone and may reduce the need for bariatric surgery.

An energy-reduced diet with moderate protein (approx 20-30%) and increased nonfat dairy (4-5 servings/day) combined with daily walking produces significant weight loss and fat mass reduction in overweight/obese women, with no significant difference in outcomes compared to a standard protein/dairy control diet.

To lose weight and fat, focus on creating an energy deficit through a reduced-calorie diet and regular walking. Adding moderate protein and nonfat dairy is healthy and supports the diet, but it does not provide a significant advantage over a standard calorie-restricted diet. Consistency in calorie reduction and activity is more important than specific macronutrient targets like high protein or extra dairy.