Browse the evidence

There is no conclusive evidence that varying the relative quantities of dietary carbohydrates and fats (macronutrient partitioning) significantly affects the degree of weight loss or the duration of weight maintenance beyond the effects of total caloric intake.

Do not expect a specific macronutrient ratio (low-carb vs. low-fat) to give you a metabolic advantage for long-term weight loss if you are eating the same number of calories. The science shows that both diets work equally well for weight maintenance when calories are matched. Focus on finding a diet you can adhere to long-term, as compliance is the primary driver of success, not the specific ratio of carbs to fats.

Intensive lifestyle interventions (diet and exercise) alone do not significantly reduce cardiovascular event risk in overweight/obese adults with type 2 diabetes compared to usual care, whereas weight loss achieved through metabolic surgery significantly reduces complications and mortality.

While healthy eating and exercise are important, they might not be enough to protect your heart if you have type 2 diabetes and are overweight. The Look AHEAD study showed that intensive lifestyle changes didn't lower heart attack or stroke risk compared to standard care. However, losing a significant amount of weight (10% or more) did help. For some, metabolic surgery offers the best chance to reduce complications and live longer. Talk to your doctor about combining lifestyle changes with medications or other treatments.

Longitudinal changes in body composition (fat mass, lean mass, or waist circumference) are not significantly associated with the risk of myocardial infarction (MI) in patients with type 2 diabetes.

In type 2 diabetes, losing weight and fat does not significantly reduce your risk of having a heart attack (myocardial infarction). However, it does significantly reduce your risk of heart failure. Therefore, weight loss remains crucial for heart health, but for different reasons than preventing heart attacks.

Metabolic adaptation (a reduction in resting metabolic rate beyond what is predicted by body composition changes) is minimal, transient, and does not predict long-term weight regain in overweight women following weight loss.

Do not blame persistent weight regain on a 'slowed metabolism' or 'adaptive thermogenesis.' While your metabolism does drop slightly when you lose weight, this effect is small, temporary, and does not predict who will regain weight. Focus on sustainable lifestyle changes and long-term support rather than trying to 'trick' your metabolism.

The doubly labeled water technique provides accurate measurements of total energy expenditure in healthy adults when performed in experienced laboratories, but significant between-laboratory variability exists that can lead to physiologically impossible results in less experienced settings.

If you are using Doubly Labeled Water to measure energy expenditure, ensure your laboratory is experienced with the technique. The method is accurate, but results vary significantly between labs. Use standardized isotope standards and calculation methods (like the 2-point or modified methods) to minimize error, especially if your subject has a low ratio of water intake to energy expenditure.

When energy balance is maintained, exercise does not induce negative fat balance in lean sedentary, obese sedentary, or lean endurance-trained individuals.

If you exercise but eat back the calories you burned, you will not lose fat. To lose fat through exercise, you must not replace the calories expended. Simply adding exercise without adjusting diet will not create a negative fat balance.

In advanced CKD and dialysis patients, higher BMI (including morbid obesity) is associated with better survival outcomes, a phenomenon known as the 'obesity paradox'.

If you are on dialysis, do not try to lose weight. Your higher body weight is actually protecting your life. Focus on eating enough protein and calories to maintain your muscle mass, as losing weight is dangerous for dialysis patients.

Dieting acts as a self-imposed famine that triggers physiological starvation responses, leading to long-term weight gain and obesity rather than sustained weight loss.

Stop dieting. The paper argues that dietary restriction acts like famine, triggering biological mechanisms that cause long-term weight gain. Instead of restricting calories, focus on accepting your body's natural weight regulation, as lifetime maintainers do not use dieting strategies.

Low total energy expenditure (TEE), specifically reduced expenditure for physical activity, facilitates rapid weight gain in genetically susceptible individuals by providing surplus energy for fat deposition.

If you are prone to weight gain, your body may naturally expend less energy through physical activity than others. This isn't just a result of being overweight; it's a mechanism that drives weight gain. To counteract this, you must consciously increase your physical activity levels, as your body may not naturally adjust its expenditure to match higher intake. While you may not see massive fat loss from exercise alone, it is a necessary lever to prevent surplus energy storage.

Overfeeding healthy young men of normal body weight does not trigger significant energy-wasting mechanisms (like adaptive thermogenesis); instead, 85-90% of excess energy intake is deposited as body mass.

If you are a healthy young man, your body does not have a strong 'safety valve' to burn off excess calories. If you consistently eat 1000 calories more than you need, 85-90% of those extra calories will be stored as body mass. Do not rely on your body to naturally adjust its metabolism to prevent weight gain.

In obese women, body fat distribution (upper vs. lower body) does not significantly correlate with basal metabolic rate (BMR), sleeping metabolic rate (SMR), or 24-hour energy expenditure (24h-EE).

For obese women, where you carry your fat (waist vs. hips) does not appear to change your resting metabolic rate. Weight loss strategies should focus on caloric balance rather than targeting specific fat distribution areas for metabolic boost.

Metabolic surgery, which yields approximately 25% weight loss at 10 years, is associated with a 44% lower risk of invasive cancer compared to non-surgical patients.

For individuals with severe obesity, metabolic surgery can lead to significant weight loss and a substantially lower risk of invasive cancer. Discuss with your doctor if you are a candidate.

Anthropometric measures (BMI, waist circumference, waist-to-hip ratio) are recommended as feasible, cost-effective core measures for obesity clinical trials, despite being less accurate than imaging methods like DXA or MRI.

For obesity research, simple measurements like height, weight, and waist circumference are the standard starting point because they are feasible and cost-effective. While they are less precise than advanced imaging, they are sufficient for tracking general trends in body composition across large groups.

Current energy intake recommendations for pregnant women with obesity overestimate total daily energy expenditure (TDEE), potentially promoting excess gestational weight gain.

Standard calorie recommendations for pregnant women with obesity are likely too high. This study suggests that following these standard guidelines may lead to excessive weight gain because they overestimate how many calories these women actually burn. Healthcare providers should consider lower energy targets or more personalized metabolic assessments for obese pregnant women to prevent excess gestational weight gain.

The early improvement in hepatic insulin sensitivity after RYGB is primarily driven by postoperative caloric restriction and reduced liver fat, rather than surgery-specific anatomical effects.

Early improvements in liver function after gastric bypass are largely due to the immediate reduction in calorie intake and liver fat, not just the surgery itself. Maintaining a caloric deficit is essential to sustain these early metabolic benefits.

Housing mice at thermoneutrality (30°C) rather than standard room temperature (22°C) does not improve the prediction of human drug efficacy for weight loss, as the direction and magnitude of drug effects vary by mechanism regardless of temperature.

This paper is a methodological critique for preclinical researchers, not a direct guide for human behavior. It suggests that while standard mouse housing (22°C) creates thermal stress, simply moving to thermoneutrality (30°C) does not solve the translatability problem for obesity drugs. Researchers should test drugs at both temperatures to understand mechanism-specific responses, as efficacy can flip depending on the thermal environment.

GLP-1 receptor agonists (like semaglutide) and hFGF21 analogs produce similar weight loss efficacy in mice regardless of whether they are housed at standard room temperature (22°C) or thermoneutrality (30°C).

For GLP-1 and hFGF21 drugs, the mouse model's housing temperature is less critical for predicting efficacy magnitude than for other drug classes. These drugs work robustly in both cold-stressed and thermoneutral environments.

GDF15 analogs are significantly more effective at inducing weight loss in mice housed at standard room temperature (22°C) compared to thermoneutrality (30°C), with efficacy dropping by half at higher temperatures.

If developing GDF15-based therapies, preclinical data from cold-housed mice may overestimate efficacy compared to thermoneutral conditions. The drug's effectiveness is halved when mice are not cold-stressed.

Peptide YY (PYY) analogs show greater weight loss efficacy in mice housed at thermoneutrality (30°C) compared to standard room temperature (22°C), contrary to the trend seen with GDF15.

For PYY-based therapies, preclinical data from thermoneutral mice may better reflect potential efficacy than data from cold-stressed mice, where the drug appears largely ineffective.

Bariatric surgery significantly reduces all-cause mortality, cardiovascular mortality, and major adverse cardiovascular events (MACE) compared to medical therapy in patients with severe obesity and Type 2 Diabetes.

For severe obesity and Type 2 Diabetes, bariatric surgery is the most effective treatment for reducing heart disease risk and death. It significantly lowers the risk of heart attack, stroke, and heart failure compared to medical therapy alone. Discuss surgical options with a specialist if lifestyle changes and medications are insufficient.

Bariatric surgery significantly reduces the risk of developing heart failure and improves mortality in patients with existing heart failure and obesity.

For severe obesity, bariatric surgery is a highly effective treatment that can prevent heart failure and significantly improve survival in those who already have it. It is safe and can even be used as a bridge to heart transplantation in severe cases. Consult with a bariatric surgeon and cardiologist to see if you are a candidate.

Obese individuals attempting self-directed weight loss do not increase energy expenditure or physical activity patterns (NEAT, EAT, steps) to achieve weight loss; weight loss is driven by reduced energy intake (modified nutritional habits) rather than increased energy expenditure.

If you are trying to lose weight on your own, do not rely on increasing your physical activity or exercise to drive the weight loss. This study shows that people who successfully lose weight do not increase their energy expenditure, steps, or exercise time compared to those who don't. Instead, focus on modifying your nutritional habits, specifically by reducing the frequency of unfavorable foods (high fat, high glycemic index) and increasing favorable foods. Weight loss is achieved through dietary changes, not by moving more.

The reduction in schizophrenia risk associated with GLP-1 receptor agonists is mediated by body mass index (BMI) rather than glycemic control.

The mental health benefits of GLP-1 drugs for schizophrenia risk appear to come from weight loss, not from lowering blood sugar. This means that interventions focusing on weight management (whether through GLP-1 drugs or other means) may be the key to reducing this specific psychiatric risk. It highlights the importance of addressing obesity in mental health prevention strategies.

Overweight status (BMI 25-<30) is not associated with increased risk for most cardiovascular outcomes and may have a neutral or slightly protective effect on all-cause mortality compared to normal weight.

Being overweight is not as strongly linked to heart disease or death as obesity. While weight management is still beneficial, the urgency is lower for overweight individuals compared to those with obesity. Focus on overall health metrics rather than just weight.