Browse the evidence

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.

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.

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.

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.

Intermittent Energy Restriction (IER) using a 5:2 diet pattern is equally effective as Continuous Energy Restriction (CER) for reducing body weight and blood pressure in overweight and obese patients with hypertension over a 6-month period.

If you have high blood pressure and are overweight, trying a 5:2 diet (eating very little, around 500-600 calories, on two non-consecutive days a week and eating normally the other five days) can lower your blood pressure and help you lose weight just as well as eating slightly less every single day. You should consult your doctor to adjust any blood pressure or diabetes medications, as your needs may change with weight loss.

Alternate-day modified fasting (ADMF) produces greater weight loss and BMI reduction compared to daily calorie restriction (CR) in overweight/obese women over 8 weeks.

If you are an overweight woman looking to lose weight, try Alternate-Day Modified Fasting. On fasting days, eat only 25% of your calculated daily calories (mostly lunch). On feeding days, eat 100% of your daily calories. Keep your macronutrient ratio at 15% protein, 30% fat, and 55% carbs. This method may help you lose more weight and stick to the diet better than eating less every day.

Intermittent fasting significantly reduces body weight and BMI in overweight and obese adults compared to control diets, with alternate-day fasting showing superior weight loss effects compared to time-restricted eating.

Intermittent fasting is an effective strategy for weight loss in overweight and obese individuals. Alternate-day fasting appears to offer greater weight loss benefits than time-restricted eating. To implement, choose a method (like ADF, TRE, or 5:2) that fits your lifestyle, ensuring you maintain a caloric deficit during fasting periods. Consistency over 12+ weeks yields the best results for body composition.

In individuals with type 2 diabetes, combining caloric restriction with high-dose exercise (300-330 minutes/week) significantly reduces fat mass percentage more than caloric restriction alone, while preserving fat-free mass.

For people with type 2 diabetes, dieting alone causes muscle loss along with fat. To maximize fat loss and keep muscle, you must add exercise. Aim for 6 sessions a week (300-330 mins total) mixing cardio and weights. If that is too much, start with 3 sessions (150-165 mins), which still burns more fat than dieting alone without losing muscle.

High-dose exercise (300-330 min/week) preserves fat-free mass during caloric restriction in type 2 diabetes, whereas moderate exercise (150-165 min/week) and diet-only interventions result in fat-free mass loss.

If you have type 2 diabetes and are dieting, you risk losing muscle. To stop this, you need high-volume exercise (at least 5 hours a week) including weights. Standard '150 minutes of exercise' guidelines are not enough to protect your muscle mass during weight loss.

Combined exercise and dietary interventions produce significantly greater body weight loss than exercise alone in adults with overweight or obesity, but do not significantly reduce ectopic fat (liver fat, visceral fat area, or intramuscular triglycerides) compared to exercise alone.

If your goal is simply to lose body weight, adding exercise to your diet will help you lose more weight than dieting alone. However, if your specific goal is to reduce ectopic fat (fat in your liver, visceral area, or muscles), simply combining diet and exercise may not be more effective than exercise alone. You may need to focus on specific types of exercise or longer durations (>12 weeks) to target these specific fat depots, as general weight loss does not guarantee ectopic fat reduction.

Long-term interventions (>12 weeks) involving either exercise or caloric restriction are successful in decreasing visceral fat area (VFA) in adults with overweight or obesity, whereas short-term interventions may not be.

To reduce visceral fat, you need to stick with your exercise or diet plan for more than 12 weeks. Short-term efforts may not be enough to target this specific type of fat. Consistency over time is key.

A hypocaloric diet leads to statistically significant weight loss in adults with overweight or obesity regardless of whether the macronutrient composition is high-protein or high-carbohydrate.

To lose weight, you must create a caloric deficit. This study shows that whether you get those calories from protein or carbohydrates matters less than the total calorie reduction. A daily reduction of 500 kcal led to significant weight loss regardless of the macronutrient split. Choose the diet composition you can sustain best while maintaining this deficit.

A modest reduced-calorie diet (75% of energy requirements) for two months significantly improves lipid profiles, blood pressure, and specific inflammatory markers (ICAM-1, MCP-1) in overweight/obese adults with cardiovascular risk factors.

If you are overweight or obese and have high blood pressure, cholesterol, or blood sugar, cutting your daily calories to 75% of what your body normally burns (a 25% reduction) for two months can significantly lower your bad cholesterol, triglycerides, and blood pressure. It also reduces specific markers of blood vessel inflammation. You do not need to change your exercise routine, but you should avoid omega-3 supplements during this period. Focus on filling your reduced calories with vegetables, fruits, and lean proteins to stay full.

A daily caloric deficit of 500-1,000 kcal (low-calorie diet) produces a weight loss of 0.5-1.0 kg per week and up to 10% body weight over 6 months.

To lose weight steadily, reduce your daily calorie intake by 500 to 1,000 calories compared to what you normally eat. This moderate deficit typically results in losing 0.5 to 1.0 kg per week. Over six months, this approach can help you lose about 10% of your body weight. Focus on sustainable habits rather than extreme restriction.

In well-trained males, full-body resistance training routines produce significantly greater fat mass loss than split-body routines when weekly training volume is matched.

If you are an experienced male lifter trying to lose fat, switch to a full-body routine (training all major muscle groups 5 days a week) instead of splitting body parts across the week. Keep your total weekly sets the same (around 75 sets). This approach will likely help you lose more fat because you will feel less sore and move more during the rest of your day, burning more calories overall.

Progressive weight loss exceeding 30% induces 100% remission of hyperinsulinemia (HI) and insulin resistance (IR) in individuals with overweight or obesity, whereas lower weight loss thresholds yield partial or no remission.

If you have high insulin or insulin resistance, losing a small amount of weight (5-10%) will help your health, but it likely won't cure the metabolic issue. To fully reverse hyperinsulinemia and insulin resistance, you generally need to lose more than 30% of your body weight through a sustained, intensive lifestyle and medical program over a year.