Browse the evidence

Formula very low-energy diets (VLEDs, <800 kcal/day) and low-energy diets (LEDs, 800–1200 kcal/day) achieve clinically significant short-term weight loss (10–15% bodyweight) and can induce type 2 diabetes (T2D) remission when combined with structured weight maintenance programs.

If you have recently diagnosed Type 2 Diabetes and obesity, a structured program using formula meals (under 800-1200 calories/day) for 3-5 months, followed by a gradual return to normal food and long-term support, can put your diabetes into remission in nearly half of participants. This requires medical supervision to adjust diabetes medications safely, but it is a viable alternative to surgery for many.

Calorie restriction is more effective for obesity treatment than dietary fat restriction, producing significantly greater weight loss and better long-term maintenance.

To lose weight and keep it off, focus on limiting your total daily calories (aiming for 1000-1200 kcal depending on your size) rather than just cutting fat. While you can eat low-fat foods, if you don't control the total energy, you won't lose weight. Use behavioral strategies like self-monitoring to stay within your calorie goal.

Preventing population-level weight gain in China requires closing a daily energy gap of approximately 45 kcal, achievable through small lifestyle changes such as reducing energy intake by 2-3% or adding 10-15 minutes of brisk walking daily.

To prevent weight gain, you do not need to overhaul your diet or exercise routine. Simply reduce your daily calorie intake by about 45 calories (roughly 2-3% of a standard diet) or add 10-15 minutes of brisk walking to your day. These small, sustainable changes are sufficient to offset the average energy surplus driving population weight gain.

Dietary behavior modification inducing sustained weight loss (approx. 10%) in overweight/obese lactating women significantly improves cardiovascular risk factors, including reduced waist circumference, total/LDL cholesterol, and fasting insulin, and increased HDL cholesterol.

For overweight or obese women in the postpartum period, a structured dietary intervention aiming for a modest 0.5 kg/week weight loss through a 500 kcal daily deficit can significantly improve long-term cardiovascular health markers (like cholesterol and insulin sensitivity) without harming breast milk. Exercise alone was not effective in this study, suggesting diet is the primary lever for metabolic improvement in this specific context.

Ad libitum consumption of fat-reduced diets produces significant weight loss over long-term periods (up to 7 years) and reduces cardiovascular risk factors and type 2 diabetes incidence.

To lose weight sustainably, reduce your total fat intake by about 10% of your daily calories without counting every calorie. Focus on filling your plate with fruits, vegetables, and whole grains to keep you full. Combine this with regular exercise to maximize health benefits and reduce diabetes risk.

A 6-month lifestyle intervention combining moderate caloric restriction (250–350 kcal/day deficit) with low-intensity aerobic exercise (walking at 50–60% heart rate reserve) effectively resolves metabolic syndrome in obese postmenopausal women, primarily through reductions in fat mass.

For obese postmenopausal women, a 6-month program of modest calorie cutting (250-350 kcal/day) combined with regular, low-intensity walking (50-60% of max heart rate) is highly effective at reversing metabolic syndrome. The key is fat loss, not high-intensity cardio. This approach also helps preserve muscle mass, which is critical for older adults.

Caloric restriction (20-30% reduction) significantly improves cardiometabolic health by reducing body weight, BMI, fat mass, total cholesterol, and LDL, while having no significant effect on blood pressure or HDL.

To improve metabolic health, reduce your daily caloric intake by 20-30% while ensuring you still get all essential nutrients. Expect significant weight loss and improved cholesterol levels, but do not expect blood pressure or HDL changes to be guaranteed outcomes.

Time-restricted eating (TRE) with an 8-hour daily eating window significantly reduces body weight and fat mass in adults with obesity compared to control groups, particularly when the intervention lasts longer than 12 weeks.

If you have obesity, try restricting your eating to an 8-hour window each day (e.g., 10 AM to 6 PM). This approach is more effective for weight and fat loss than no time restriction, especially if you stick with it for more than 3 months. While it doesn't significantly change blood sugar or cholesterol markers in obese adults, it is a viable strategy for weight management. Be aware that adherence may be challenging due to social obligations, so consistency is key.

A low-energy total diet replacement (TDR) intervention (800-820 kcal/day formula diet) combined with behavioral support significantly reduces body weight, insulin requirements, and improves quality of life in patients with long-standing type 2 diabetes and obesity treated with insulin.

If you have long-standing type 2 diabetes and take insulin, a structured low-calorie formula diet (around 800 calories/day) for 12 weeks, followed by a gradual return to solid foods with ongoing support, can help you lose significant weight and potentially reduce or stop your insulin. This must be done under medical supervision to adjust your insulin doses safely and prevent low blood sugar. The key is the initial energy deficit combined with behavioral support.

A 12-week energy-restricted diet intervention produces similar beneficial reductions in body weight, fat mass, and insulin resistance in both metabolically abnormal obese (MAO) and metabolically healthy but obese (MHO) premenopausal women.

If you are an obese premenopausal woman, whether your blood markers are currently normal (MHO) or abnormal (MAO), a structured 12-week diet creating a moderate caloric deficit (approx. 600 kcal/day below your needs) will effectively reduce your weight and improve your metabolic health. Do not skip intervention just because you feel 'healthy' now; the benefits of weight loss apply to you just as much as to those with metabolic issues.

Intermittent Energy Restriction (IER) diets, including Alternate-Day Fasting (ADF) and Time-Restricted Feeding (TRF), produce weight loss and metabolic improvements (reduced triglycerides, LDL, and blood pressure) that are comparable to Continuous Energy Restriction (CER) diets when total caloric intake is matched.

If you struggle with daily calorie counting, try Intermittent Energy Restriction. You can either fast on alternate days (eating very little or nothing on fast days) or restrict your eating to a specific window (e.g., 8 hours) each day. The goal is to reduce total weekly calories, not necessarily to eat less every single day. Expect to lose about 3-8% of your body weight over 2-3 months, similar to what you would get from eating less every day.

Consuming high-fiber rye products as part of a hypocaloric diet for 12 weeks causes greater body weight and body fat loss compared to consuming refined wheat products, independent of subjective appetite responses.

If you are trying to lose weight on a calorie-restricted diet, replace your refined wheat products (bread, cereal, crispbread) with high-fiber rye products. In this 12-week study, this swap resulted in significantly more weight and fat loss (1.08 kg and 0.54% body fat more) compared to wheat, even though participants didn't feel less hungry. You must still maintain your calorie deficit; rye is not a free pass to eat more calories.

Adhering to a low energy-dense (LED) diet significantly reduces total daily energy intake and improves appetite control (increased fullness, reduced hunger/cravings) in overweight and obese women, leading to greater weight loss compared to standard calorie-restriction programs.

To lose weight effectively, focus on eating foods with low energy density (high volume, low calories, like vegetables, fruits, lean proteins) rather than just counting calories. This approach allows you to eat until you are full, reduces hunger and cravings, and makes sticking to your diet easier and more enjoyable than strict calorie restriction.

Individual reductions in ad libitum energy intake explain a significant portion (23-58%) of the variation in subsequent weight loss, linking acute appetite effects to long-term weight management.

Focus on how full you feel. Studies show that when you eat foods that make you feel fuller, you naturally eat fewer calories, and this reduction in calories directly leads to more weight loss. It's not just about willpower; it's about choosing foods that work with your body's hunger signals.

A 3-month low-calorie diet (1,200–1,500 kcal/day) significantly reduces the thickness of intra-abdominal preperitoneal and visceral fat layers in obese women, with preperitoneal fat showing the strongest correlation to overall weight loss.

If you are an obese woman aiming to lose weight, a strict low-calorie diet (1,200-1,500 kcal/day) for 3 months will effectively reduce dangerous intra-abdominal fat. While waist measurements might not change dramatically, internal fat layers shrink significantly. Use sonography if available to monitor this specific loss, as it is more accurate than waist-to-hip ratios for tracking visceral fat reduction.

Fatmax training (FMT) performed for 8-20 weeks significantly reduces body weight, fat mass, and waist circumference in obese individuals without altering fat-free mass.

To lose fat without losing muscle, train at your specific 'Fatmax' intensity (where your body burns the most fat) for 8-20 weeks, 3-5 times a week. This intensity is usually moderate (40-50% of your max oxygen uptake). Do not combine this with a strict diet, as the study showed fat loss occurred even without caloric restriction. This approach preserves muscle mass while reducing total and abdominal fat.

Interval training (HIIT and SIT) produces significantly greater reductions in total body fat percentage compared to moderate-intensity continuous training (MICT) and non-exercise control (CON) in apparently healthy adults.

If you want to lose body fat, interval training (HIIT or SIT) is more effective than steady-state cardio (MICT) or no exercise. You don't need to do long sessions; even low-volume HIIT (under 15 minutes of high-intensity work per session) can be superior. This is especially true if you have overweight or obesity, or if you stick with the program for at least 12 weeks.

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.

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.

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.