Browse the evidence

A ketogenic diet (defined as <50g carbohydrates/day) significantly improves body weight, waist circumference, HbA1c, triglycerides, and HDL levels in overweight patients with Type 2 Diabetes Mellitus compared to other dietary interventions.

For overweight individuals with Type 2 Diabetes, adopting a ketogenic diet (under 50g carbs daily) is a highly effective strategy for losing weight and improving blood sugar control. This approach also tends to improve heart health markers like HDL and triglycerides, addressing common concerns about high-fat diets. Consult a doctor to manage medications, as blood sugar levels may drop significantly.

A 6-month low-calorie, high-protein diet (35% of total calories from protein) improves glucose metabolism, body composition, and cardiometabolic profiles in subjects with prediabetes or type 2 diabetes and overweight/obesity, regardless of whether the protein source is primarily animal or plant-based.

If you have prediabetes or type 2 diabetes and are overweight, switching to a diet where 35% of your calories come from protein (whether from meat, fish, eggs, beans, nuts, or soy) and restricting your total calories by 30% can significantly improve your blood sugar, weight, and heart health markers. It does not matter if you choose animal or plant proteins; the key is the high-protein, low-calorie pattern itself. Stick to this for at least 6 months for best results.

High-protein isocaloric diets (HPD) preserve or increase muscle mass during weight loss, whereas very low-energy diets (VLED) significantly decrease muscle mass.

If you are losing weight, ensure your protein intake is high (around 1.8g per kg of body weight). This helps you keep your muscle while losing fat. Very low-calorie diets without high protein will cause you to lose muscle mass.

Ketogenic diets (KD) significantly reduce waist circumference compared to other dietary interventions, indicating superior reduction in central adiposity.

If you want to specifically target belly fat (waist circumference), a ketogenic diet (very low carb, high fat) is effective. It significantly reduces waist size compared to other diets, even when calories are not restricted.

Isocaloric diets with macronutrient distribution (LCD, KD, HPD) result in greater weight loss than caloric restriction diets (LED, VLED) in obese women over 12 weeks.

You can lose weight without counting calories if you focus on macronutrients. Diets that adjust carbs, protein, or fat ratios (like Keto, Low-Carb, or High-Protein) can lead to greater weight loss than simple calorie restriction over 12 weeks.

Very Low-Calorie Ketogenic Diet (VLCKD) produces superior weight loss compared to low-carbohydrate diets and is recommended for severe obesity and specific metabolic conditions.

VLCKD is a very strict, low-calorie (<800 kcal) ketogenic diet that produces superior weight loss compared to standard low-carb diets. It is recommended for severe obesity and specific metabolic conditions under medical supervision. It is not suitable for everyone and has strict contraindications.

The superiority of low-carbohydrate diets for weight loss and body fat percentage reduction is most pronounced in subgroups with longer follow-up (≥6 months), younger age (<60 years), and very low carbohydrate intake (<10% carbs).

To maximize weight loss benefits from a low-carb diet, aim for very low carbohydrate intake (<10% of calories) and maintain the diet for at least 6 months. This approach is particularly effective for individuals under 60 years of age.

Mediterranean Diet (MD) interventions significantly improve liver enzymes (ALT, AST), Fatty Liver Index, and liver stiffness in NAFLD patients, often with higher adherence than other diets.

Adopting a Mediterranean-style dietary pattern is an effective strategy for improving liver health in NAFLD. This involves increasing fiber, fruits, nuts, and healthy fats (like olive oil) while reducing refined carbohydrates and sodium. This approach not only improves liver enzymes and fat content but also tends to have higher patient adherence compared to other restrictive diets.

Ketogenic diets, characterized by high fat and low carbohydrate intake, improve metabolic health and reduce body weight by shifting metabolism towards fatty acid oxidation and ketone production.

Adopt a ketogenic diet by limiting carbohydrates to under 40 grams per day, while increasing fat intake and keeping protein moderate. This shift forces your body to burn fat for fuel, which can lead to weight loss and improved metabolic markers.

A low-carbohydrate diet (26% of calories) significantly reduces serum triglycerides when combined with calorie restriction, but not when low-carbohydrate is applied without calorie restriction.

If you want to improve your blood triglyceride levels, a low-carbohydrate diet alone may not be enough. You need to combine low-carbohydrate intake (26% of calories) with calorie restriction (1200-1500 kcal/day) to see significant reductions in triglycerides. This combination was the only one to significantly lower triglycerides in this study.

Low-fat diets (LFD) result in greater reductions in Total Cholesterol (TC) and Low-Density Lipoprotein (LDL) cholesterol compared to low-carbohydrate diets (LCD) over a duration of 6 to 23 months.

If your primary health concern is high LDL or Total Cholesterol, a low-fat diet (less than 30% of calories from fat) is likely more effective than a low-carb diet for lowering these specific numbers over the next 6-23 months. Note that this benefit disappears after 24 months.

Ultra-processed foods drive obesity primarily through their high glycemic load and disrupted cellular structure, which accelerates digestion and hormonal response, rather than just their energy density.

Minimize ultra-processed foods, especially those high in carbohydrates. Whole foods retain cellular structures that slow digestion and blunt glycemic spikes, reducing the hormonal drive for fat storage.

A 2-week ketogenic diet significantly upregulates adaptive immune pathways (T cell activation, oxidative phosphorylation) and alters microbiome amino acid metabolism, whereas a vegan diet upregulates innate immune pathways (antiviral responses, type I interferon) and erythrocyte differentiation.

Switching to a ketogenic diet for just two weeks shifts your immune system toward adaptive responses (T cells, oxidative phosphorylation), while a vegan diet shifts it toward innate/antiviral responses. This suggests diet can be used as a tool to modulate specific immune pathways, potentially relevant for managing inflammation or infection risk, though long-term disease outcomes require further study.

Low-carbohydrate diets offer superior short-term glycaemic control (HbA1c reduction) compared to high-carbohydrate diets, but this benefit is not maintained at 12 months.

If you have type 2 diabetes, a low-carbohydrate diet can help lower your HbA1c significantly in the first 6 months. However, this advantage tends to disappear after a year, likely because it is hard to stick to. Focus on a sustainable dietary pattern that you can maintain long-term.

Higher dietary protein intake (1.2-1.5 g/kg/day) combined with adequate calcium intake is associated with lower hip fracture risk and improved bone mineral density in older adults, whereas high protein with low calcium may increase fracture risk.

Aim for 1.2-1.5 grams of protein per kilogram of body weight daily, ensuring you also consume 1000-1200 mg of calcium. This combination protects against hip fractures and preserves muscle mass. Do not restrict protein out of fear of bone loss; instead, ensure your calcium intake is sufficient to support the protein.

Lipase inhibitors (orlistat and cetilistat) reduce weight by inhibiting fat absorption, but are associated with gastrointestinal side effects and are less effective in patients with diabetes.

Orlistat is a daily pill that blocks fat absorption. It is taken with meals containing fat. It can cause gastrointestinal side effects like oily stools. It is not effective for patients with diabetes.

A higher variety score of dietary protein sources (consuming appropriate quantities from more of the eight major sources: grains, meat, poultry, fish, egg, legumes) is inversely associated with the risk of new-onset diabetes.

To lower your risk of type 2 diabetes, aim to include a variety of protein sources in your diet rather than relying on just one or two. The study suggests that consuming appropriate amounts from a mix of grains, legumes, fish, poultry, and eggs is associated with a significantly lower risk of developing diabetes compared to a diet with fewer protein sources. You do not need to eliminate any specific source, but rather ensure your diet includes a broad spectrum of these foods.

Total protein intake has a U-shaped association with diabetes risk, where both very low (<10.6% of energy) and very high (≥14.0% of energy) intakes are associated with higher risk compared to moderate intake (10.6-14.0% of energy).

Avoid both very low and very high total protein intakes. The study suggests that getting 10.6% to 14.0% of your daily calories from protein is associated with the lowest risk of developing diabetes. This means you should neither severely restrict protein nor consume excessive amounts, but rather aim for a moderate level.

Specific protein sources have non-linear associations with diabetes risk: fish and legumes show inverse J/L-shaped associations (lower risk with higher intake), while red meat and poultry show J/U-shaped associations (increased risk at high intakes).

Choose your protein sources wisely. Fish and legumes are associated with lower diabetes risk, especially at higher intakes. Red meat and poultry should be consumed in moderation, as high intakes are associated with increased risk. Eggs and whole grains are also beneficial when consumed in appropriate amounts.

In females with type 2 diabetes, the combination of low fat mass and low muscle mass is synergistically associated with higher glycated hemoglobin (A1C) levels compared to other body composition phenotypes.

If you are a woman with type 2 diabetes, do not assume that being thin means your blood sugar is well-managed. This research shows that having low body fat AND low muscle mass is a specific risk factor for higher blood sugar levels. To improve your A1C, focus on building muscle mass through resistance training, rather than just trying to lose weight or stay thin.

In males with type 2 diabetes, high fat mass is significantly associated with higher A1C, but muscle mass does not significantly influence A1C levels.

If you are a man with type 2 diabetes, your blood sugar levels are more closely linked to your body fat than your muscle mass. While building muscle is healthy, prioritizing fat loss through diet and exercise is likely to have a more direct impact on lowering your A1C levels.

When essential amino acid profiles are equated, a novel plant-based protein matrix provides equivalent benefits to whey protein for body composition, strength, power, and aerobic performance in trained futsal players over an 8-week period.

If you are an athlete consuming enough total protein (over 1.6g/kg body weight per day), the specific source of your protein supplement (plant vs. whey) does not matter for muscle gain, strength, or performance, provided the plant protein is formulated to match the essential amino acid profile of whey. You can choose plant-based options without sacrificing results.

GLP-1 receptor agonists (semaglutide) and dual GLP-1/GIP agonists (tirzepatide) cause significant lean mass loss during weight loss, with semaglutide losing approximately 45% of total weight as lean mass and tirzepatide losing 25.7%, posing a specific risk of frailty and fractures in older populations.

If you are taking semaglutide or tirzepatide, be aware that a significant portion of your weight loss (up to 45% for semaglutide) comes from lean mass, not just fat. This is especially risky if you are over 60. Discuss strategies to preserve muscle, such as resistance training or potentially newer combination therapies, with your provider.

Male physique athletes lose significantly more lean mass than female athletes during competition preparation, despite similar reductions in fat mass and muscle size.

Men preparing for physique competitions should be aware they may lose more muscle than women during a cut, likely because they reach lower body fat levels. Prioritizing protein and minimizing the depth of the cut may help preserve muscle.