Browse the evidence

The reduction in energy intake from lower energy density meals is linearly related to the change in energy density, with stronger effects in adults than children and in entrée designs compared to preloads.

The calorie-reducing effect of low energy density foods is strongest in adults and when consumed as main meals (entrées). In children, the effect is smaller, and preloads may be less effective than main meals.

Adherent caloric restriction in overweight/obese women induces metabolic adaptation, evidenced by a significant decrease in Resting Energy Expenditure (REE) that exceeds the reduction predicted by changes in Fat-Free Mass (FFM).

If you are losing weight through calorie restriction, expect your resting metabolism to drop significantly (approx 10% in this study) beyond what you would predict just from losing weight. This is a biological defense mechanism, not a failure. To maintain weight loss, you must account for this lower energy expenditure, likely by adjusting your caloric intake or increasing physical activity to offset the metabolic slowdown.

Combining a hypocaloric diet with Monoselect Camellia (a green tea extract) yields superior weight loss compared to hypocaloric diet alone.

If you are on a calorie-restricted diet for weight loss, adding 150mg of Monoselect Camellia (a green tea extract) daily may help you lose more weight than dieting alone. This works by boosting fat oxidation and reducing lipid absorption.

Early Time-Restricted Eating (eTRE) with an 8-hour window starting before noon significantly reduces body weight and fat mass while improving glycemic markers (fasting glucose, insulin, HOMA-IR) and triglycerides in young adults with delayed sleep-wake cycles, whereas late TRE (starting after noon) fails to produce these metabolic benefits.

If you are a young adult with a late sleep schedule, try shifting your eating window to start before noon (e.g., 8am-4pm or 9am-5pm) for 4 weeks. Ensure you get about 20g of extra protein daily (via snacks or shakes) to protect muscle. This specific timing appears necessary to reduce fat and improve blood sugar control; starting your window after noon may not yield these metabolic benefits.

Men lose more absolute weight than women using the MetaWell program, but women have a higher proportion of achieving clinically significant weight loss (>5% body weight).

Both men and women can achieve significant weight loss with this program. While men tend to lose more total kilograms, women are slightly more likely to hit the clinically significant 5% weight loss milestone. Focus on your own progress rather than comparing absolute numbers with the opposite sex.

Seven days of a short-term ketogenic diet (KD) in endurance-trained males significantly increases maximal fat oxidation rates (approx. 1.8-fold) and shifts substrate utilization toward fat, while simultaneously causing a loss of both fat mass and fat-free mass.

If you are an endurance athlete, switching to a strict ketogenic diet for just one week will significantly boost your body's ability to burn fat during exercise. However, expect to lose about 2.4 kg of body weight, which includes both fat and some fat-free mass (likely partly water/glycogen). Your maximal power output and aerobic capacity remain unchanged in the short term, but be aware that high-intensity performance may suffer in longer-term adaptations not captured here.

Intermittent energy restriction (IER) produces superior short-term weight loss and fat mass reduction compared to continuous energy restriction (CER) in primary care settings, but is associated with higher attrition and rapid weight regain after intervention cessation.

If you try Intermittent Energy Restriction (eating very little on 2 days, normal on 5), you might lose weight faster in the first 6 months than if you cut calories every day. However, be aware that this approach is harder to stick with long-term; many people quit or regain the weight once they stop the strict fasting days. It works best if you have medical support to manage side effects like dizziness.

Intermittent energy restriction (IER) leads to greater reductions in systolic blood pressure and fat mass compared to continuous energy restriction (CER) in the short term, but these benefits are transient and revert to baseline after the intervention ends.

IER can improve blood pressure and reduce fat mass more effectively than daily calorie restriction in the short term. However, these health benefits disappear if you stop the diet, so maintaining the lifestyle change is critical for sustained cardiovascular health.

A ketogenic diet promotes rapid fat mass loss in obese individuals, primarily through caloric restriction and appetite suppression rather than a unique metabolic advantage.

If you are obese, a ketogenic diet can help you lose fat quickly, but this is largely because it helps you eat fewer calories by suppressing appetite (lowering ghrelin). It is not magically better than other diets if you eat the same number of calories. Focus on the caloric deficit and the ease of appetite control.

A ketogenic diet maintains resistance exercise performance and does not impair strength gains, even if there is a slight loss in lean body mass.

If you lift weights, you can switch to a ketogenic diet without losing your strength. You might lose a small amount of lean mass, but your power and strength gains will be similar to those on a high-carb diet. Focus on your training intensity.

A time-restricted eating protocol with a 16-hour fasting window (16:8) significantly reduces body mass and absolute fat mass in metabolically healthy, non-trained individuals, whereas 12-hour and 14-hour fasting windows do not produce significant changes.

If you are healthy and not trying to build muscle, try eating all your meals within an 8-hour window (e.g., 10am to 6pm) and fasting for the other 16 hours daily for 8 weeks. Do not try to restrict calories; just stick to the timing. You may lose fat mass without changing how much you eat, but 12-hour or 14-hour windows likely won't work for you.

Bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy) produces comparable long-term weight loss and metabolic improvements in patients with metabolic syndrome compared to those without it.

If you have severe obesity and metabolic syndrome, bariatric surgery is a highly effective option that yields long-term weight loss and metabolic improvements comparable to those without metabolic syndrome. It is currently the most effective intervention for severe cases.

Recent weight losers (≥10% loss within the past year) achieve weight loss primarily through reduced fat intake and increased physical activity, without necessarily reducing absolute total calorie intake compared to overweight/obese individuals.

If you are recently trying to lose weight, focus on reducing your fat intake and increasing your physical activity. You may not need to drastically cut total calories; simply swapping high-fat foods for lower-fat options and moving more can be effective.

A Low-Energy Diet (LED) of 850 kcal/day produces statistically equivalent weight loss and long-term maintenance compared to a Very-Low-Energy Diet (VLED) of 520 kcal/day, while offering a safer profile with fewer adverse events and reduced need for medical monitoring.

You do not need to eat fewer than 800 calories a day to lose weight effectively. A structured 850-calorie liquid diet program produces the same amount of weight loss and long-term maintenance as a more extreme 520-calorie diet, but with fewer side effects like fatigue and hair loss. Focus on a sustainable plan that includes behavioral support rather than trying to minimize calories as low as possible.

Time-restricted eating (TRE) significantly improves cardiometabolic risk factors, specifically reducing insulin, total cholesterol, and LDL concentrations.

Focus on aligning your eating window with your circadian rhythm (e.g., 16:8). This may improve insulin sensitivity and lipid profiles independently of major weight loss, particularly if you have metabolic risk factors.

Polyglucosamine (a low molecular weight chitosan) produces significantly greater weight loss and BMI reduction than orlistat 60 mg when both are used alongside caloric restriction and increased physical activity, likely due to its ability to limit both fat and carbohydrate absorption.

Take 4 polyglucosamine tablets daily with your meals while maintaining a moderate calorie deficit (approx. 500 kcal less than usual) and doing about an hour of moderate exercise daily. This study suggests this combination leads to significantly more weight loss and BMI reduction than taking orlistat 60mg under the same conditions. The benefit may be particularly strong if your diet is high in carbohydrates.

Polyglucosamine may be more effective than orlistat for weight loss in populations with high carbohydrate intake (e.g., Italian diets) because it limits both fat and carbohydrate absorption, whereas orlistat primarily limits fat absorption.

If your diet is high in carbohydrates (like pasta or bread), polyglucosamine might offer a weight loss advantage over orlistat because it appears to block the absorption of both fats and carbs, while orlistat only blocks fats. This is based on a secondary observation in this study, not the primary result.

Combining continuous energy restriction (CER) with 16/8 time-restricted feeding (TRF) yields equivalent weight and fat loss to CER alone, but superior preservation of fat-free mass and skeletal muscle.

If you are trying to lose weight while keeping your muscle, adding an 8-hour eating window (like 12pm-8pm) to your calorie deficit won't make you lose fat faster than just eating fewer calories. However, it may help you keep more muscle mass. Focus on hitting your protein and calorie targets; the timing is a tool for adherence or muscle sparing, not a magic fat-loss multiplier.

CER alone increases cortisol levels, whereas CER combined with 16/8 TRF does not, suggesting TRF may mitigate the stress response to caloric restriction.

Caloric restriction can raise stress hormones like cortisol, which might hinder muscle retention. If you are doing a diet, adding an eating window might help keep these stress hormones lower than if you just restrict calories without timing constraints.

A 6-week Mediterranean diet combined with 5 days of semi-fasting (600-700 kcal) produces weight loss and body composition improvements equivalent to a standard hypocaloric Mediterranean diet without fasting.

You can lose weight effectively by simply reducing your daily calories by 500 kcal while following a Mediterranean diet pattern. Adding a 5-day semi-fast period (consuming 600-700 kcal of liquid/pureed meals) does not provide a significant advantage in weight loss over the standard diet alone. If you choose to try the semi-fast, be aware that it requires significant preparation and may not be sustainable for everyone long-term.

Combining a hypocaloric diet with Monoselect Camellia (a green tea extract) yields superior weight loss compared to hypocaloric diet alone.

If you are following a calorie-restricted diet for weight loss, adding 150mg of Monoselect Camellia (a green tea extract) daily may help you lose more weight than dieting alone. This combination was identified as one of the most effective strategies in a large network meta-analysis of obesity treatments.

Intermittent fasting (IF) produces a statistically significant greater reduction in Body Mass Index (BMI) compared to continuous energy restriction (ER), although the absolute difference in total body weight loss is not statistically significant.

If you are trying to lose weight, intermittent fasting may help you reduce your BMI slightly more than just counting calories every day, even if the scale doesn't move much faster. Try a 16:8 schedule (fast for 16 hours, eat within 8 hours) or alternate-day fasting. Be aware that you might feel dizzy, while those just cutting calories might get more headaches. The key is consistency with whichever method you choose.

Intermittent fasting and continuous energy restriction produce similar improvements in blood pressure (systolic and diastolic), LDL cholesterol, and HDL cholesterol, with no statistically significant differences between the two methods.

If your goal is to lower blood pressure or improve cholesterol, you do not need to fast. Reducing your overall calorie intake through standard dieting is just as effective as intermittent fasting for these specific heart health markers. Focus on the total amount of food you eat rather than when you eat it for these outcomes.

Intermittent fasting and continuous energy restriction produce similar improvements in fasting plasma glucose levels, with no statistically significant difference between the two methods.

If your goal is to improve blood sugar levels, you do not need to fast. Reducing your overall calorie intake through standard dieting is just as effective as intermittent fasting for glycemic control. Focus on the total amount of food you eat rather than when you eat it for these outcomes.