Browse the evidence

Adherence to intermittent fasting regimens is generally high (>80%) in short-term studies (≤3 months) but drops significantly in long-term studies (>3 months).

Intermittent fasting is easy to stick to for the first 3 months, but adherence drops significantly thereafter. If you plan to fast long-term, expect a drop in adherence and consider modified approaches (like MADF) to sustain it.

Genetic variants in GLP1R (rs6923761) and TCF7L2 (rs7903146) influence the response to liraglutide, with specific genotypes associated with greater reductions in body fat and weight.

If you are taking liraglutide, your genetic makeup might influence how much fat or weight you lose. Some genetic variants are linked to better outcomes with this drug. This is not a reason to start or stop treatment, but may help explain individual differences in response.

A 3-month multicomponent mobile health intervention (smartphone app + smart band + brief counseling) produces statistically significant but clinically modest weight loss and body composition improvements in overweight/obese adults compared to brief counseling alone, but these benefits are not maintained at 12 months after device removal.

Using a smartphone app and fitness tracker for 3 months can help you lose a small amount of weight and improve body composition if you are overweight or obese. However, this benefit disappears after 3 months if you stop using the devices. To maintain weight loss, you must transition the habits learned during the 3-month period (like self-monitoring and dietary awareness) into your daily life without relying on the technology.

Time-restricted feeding (TRF) improves insulin sensitivity and glycemic control (including reduced glucose variability and HbA1c) in individuals with overweight or obesity, independent of significant weight loss in some studies.

If you have insulin resistance or pre-diabetes, try shifting your eating window to end earlier in the evening (e.g., 8 PM) and start later in the morning (e.g., 4 PM). This timing aligns with your body's natural circadian rhythms, helping to lower blood sugar spikes and improve how your body uses insulin, even if the scale doesn't move dramatically.

Alternate-Day Fasting (ADF) improves insulin sensitivity (HOMA-IR) more than Continuous Energy Restriction (CER).

If you are using Alternate-Day Fasting, you may see improvements in insulin sensitivity that are not seen with standard calorie restriction. This is a potential metabolic benefit of ADF.

Semaglutide and Liraglutide reduce the risk of Major Adverse Cardiovascular Events (MACEs), whereas Naltrexone/Bupropion increases the risk of elevated blood pressure.

If you have obesity and cardiovascular risks, Semaglutide or Liraglutide are preferred because they reduce MACE risk. Avoid Naltrexone/Bupropion if you have hypertension, as it increases blood pressure risk.

Time-restricted eating (TRE) significantly reduces diastolic blood pressure (DBP) in adults with obesity, but does not significantly affect systolic blood pressure (SBP).

If you have high blood pressure, TRE might help lower your diastolic (bottom) number, but don't expect it to significantly change your systolic (top) number. This is a secondary benefit to weight loss, not a primary treatment for hypertension.

Intermittent Fasting improves metabolic health markers, including insulin sensitivity, lipid profiles (reduced triglycerides and LDL), and blood pressure, independent of weight loss magnitude, through mechanisms involving ketone body production and hormonal regulation.

Beyond weight loss, IER can improve your blood lipids and blood pressure. This happens partly because your body switches to burning fat for fuel (ketones) during fasting periods, which improves insulin sensitivity and reduces inflammation. You do not need to lose a massive amount of weight to see these metabolic benefits.

Low-carbohydrate diets produce significantly greater short-term weight loss (3-8 months) in obese individuals compared to non-carbohydrate-restricted diets, but this advantage disappears in the long term (10-30 months).

If you are obese, a low-carb diet will help you lose more weight than a standard balanced diet for the first 6-8 months. However, do not expect this advantage to last beyond a year; after 10 months, your weight loss will likely match that of someone on a balanced diet. The key benefit of LC diets in the long run is not weight loss, but improved lipid profiles (lower triglycerides, higher HDL).

Performing 250 minutes per week of self-paced aerobic exercise yields modest weight loss regardless of whether the exercise is performed in the morning (06:00–09:00) or evening (16:00–19:00).

If you want to lose weight, focus on getting 250 minutes of moderate aerobic exercise per week. It does not matter if you do it in the morning or the evening; the weight loss results are the same. Choose the time that fits your schedule best to ensure you stick with it.

An 8-week sulfur amino acid restriction (SAAR) diet (~2 g/day) in humans with overweight or obesity produces significantly greater weight loss (~20% greater) compared to a control diet (~5.6 g/day), despite maintaining similar resting metabolic rates.

To lose more weight than standard dietary restriction, try reducing sulfur amino acids (methionine and cysteine) to about 2 grams per day for 8 weeks. This can be done by eating a plant-based diet and avoiding high-sulfur supplements or specific high-sulfur foods, while allowing one flexible meal a week to maintain social life. Expect roughly 20% more weight loss than a standard control diet, even if your resting metabolism doesn't change.

Sulfur amino acid restriction (SAAR) significantly decreases serum leptin levels and increases plasma ketone bodies (beta-hydroxybutyrate and acetoacetate) compared to a control diet, indicating a shift in metabolic fuel usage.

Reducing sulfur amino acids lowers leptin (a hormone that signals fat stores to the brain) and increases ketones. This suggests your body is switching to burning fat for fuel more efficiently, which may help sustain weight loss.

Metabolic adaptation (a lower-than-predicted resting metabolic rate after weight loss) significantly increases the time required to reach specific weight loss goals, independent of dietary adherence.

If you are strictly following a calorie deficit but your weight loss has stalled or slowed significantly, it may be due to metabolic adaptation (a drop in your resting metabolic rate). This is a biological defense mechanism, not a personal failure. Adjusting expectations regarding the timeline, rather than just increasing restriction, is necessary.

VLCD intervention significantly increases Sex-Hormone-Binding Globulin (SHBG) and reduces fasting blood glucose in obese women with PCOS, whereas moderate energy deficit does not significantly alter these specific metabolic markers over 8 weeks.

VLCDs offer a metabolic advantage over moderate dieting for PCOS patients by significantly boosting SHBG and lowering fasting glucose. This suggests VLCD may be necessary to reverse the underlying insulin resistance driving hyperandrogenism in some patients.

Smartphone-only apps for weight management produce a modest but statistically significant reduction in body weight and BMI in adults with overweight or obesity, but this effect is limited to a 4-6 month window and diminishes thereafter due to lack of personalization.

Use a smartphone app for weight loss if you can commit to using it daily for 4-6 months. Expect modest results (SMD -0.33) and be prepared for weight regain if you stop using it. To maximize success, choose an app that offers some level of personalization or feedback, as generic apps have high dropout rates. This is not a long-term solution without human support or advanced AI customization.

Manipulating energy density does not significantly alter the total amount of food consumed (in grams), meaning volume intake remains constant.

Do not worry about shrinking your portions. When you lower the energy density of your food (e.g., by adding vegetables), you can eat the same amount of food by weight. This helps maintain satiety and makes the diet easier to follow long-term.

Intermittent fasting (IF) significantly reduces body weight, BMI, body fat mass, LDL cholesterol, and triglycerides in Chinese adults compared to control groups, but does not significantly reduce waist circumference, total cholesterol, HDL cholesterol, fasting glucose, or blood pressure.

If you are Chinese and looking to lose weight or improve lipid profiles, intermittent fasting (like 16:8 TRE or 5:2) is an effective strategy. Expect a modest weight loss (around 2kg) and improvements in LDL and triglycerides. However, do not expect IF to significantly lower your blood pressure or fasting glucose on its own. Adherence may be challenging due to typical eating patterns, so choose a protocol that fits your lifestyle.

Fasting-based strategies (FBS) produce slightly greater short-term weight loss and fat mass reduction compared to continuous caloric restriction (CCR) in obese adults, but these differences are not clinically significant and disappear in long-term interventions (>6 months).

If your goal is weight loss, fasting strategies (like time-restricted eating) might help you lose a bit more weight and fat in the first few months compared to simply counting calories every day. However, this advantage is small (less than 1 kg) and disappears after 6 months. Since both methods result in similar long-term weight loss, choose the approach that fits your lifestyle and is easier for you to maintain consistently.

Fasting-based strategies improve insulin sensitivity (reduced fasting insulin and HOMA-IR) in the short term compared to continuous caloric restriction, but this benefit is not sustained in long-term outcomes for fasting glucose.

If you are obese, trying fasting strategies (like time-restricted eating) may help improve your insulin sensitivity in the first few months compared to just counting calories. This is measured by lower fasting insulin levels. However, this doesn't necessarily mean you will lose more weight in the long run, so use this metabolic benefit as one factor in choosing your strategy.

Intermittent Energy Restriction (IER) produces short-term weight loss comparable to Continuous Energy Restriction (CER), but offers no significant long-term advantages in anthropometric, cardiometabolic, inflammatory, or appetite outcomes.

If you are considering Intermittent Fasting for weight loss, expect it to work similarly to standard daily calorie restriction in the short term. Do not expect it to provide better long-term health or weight maintenance results than simply counting calories every day. The choice between IER and continuous restriction should be based on which pattern you can stick to consistently, as neither offers a long-term advantage over the other.

Alternate-day modified fasting (ADMF) improves subjective sleep quality (SSQ) and reduces daytime dysfunction compared to daily calorie restriction, but does not significantly change total sleep quality (PSQI) or daytime sleepiness (ESS).

If you are an overweight woman, ADMF may help you feel more rested during the day and improve your subjective sense of sleep quality, even if it doesn't change your total sleep score or daytime sleepiness levels. Focus on the daytime benefits rather than just sleep duration.

Intermittent fasting significantly improves lipid profiles by reducing total cholesterol and LDL, but may temporarily increase triglycerides in short-term interventions (≤ 12 weeks).

Intermittent fasting improves total cholesterol and LDL, key markers for heart health. However, be aware that triglycerides may temporarily rise in the first 12 weeks as your body adapts. This is often a transient phase. If you have high baseline triglycerides, consult a healthcare provider and consider longer-term adherence to see the full lipid benefits.

Intermittent fasting significantly reduces diastolic blood pressure but has no significant effect on systolic blood pressure, fasting plasma glucose, or HbA1c in overweight and obese adults.

Intermittent fasting can help lower diastolic blood pressure, a key component of heart health. However, it may not significantly affect systolic blood pressure or blood sugar levels (FPG, HbA1c) in the short term. For comprehensive cardiometabolic health, combine IF with other lifestyle interventions and monitor your specific markers.

Intermittent Energy Restriction (IER) combined with High-Intensity Interval Training (HIIT) produces greater reductions in body weight, body fat percentage, waist circumference, and hip circumference compared to Continuous Energy Restriction (CER) combined with HIIT in overweight/obese adults, although the difference is not statistically significant in a 4-week trial.

If you are overweight or obese, combining High-Intensity Interval Training (HIIT) with an Intermittent Energy Restriction (IER) diet may help you lose more weight and body fat than a standard daily calorie-restricted diet over a short period. Specifically, eating only 30% of your daily calorie needs on two non-consecutive days a week, while eating normally on the other five days, resulted in nearly double the weight loss (4.6 kg vs 2.5 kg) compared to eating 70% of your needs every day. Although the difference wasn't statistically significant in this small 4-week study, the trend favors IER for body composition improvements.