Many diets ebb and flow in popularity, but how can you know which ones are worth your time? A myriad of factors influence how each person will respond to diet modifications. Examples include your current lifestyle, vocation, family habits, food preferences, exercise level, medical conditions, and more. Experimentation is often necessary to determine what works best for you, both now and in the long-term.
I’ve compiled a list of evidence-based diets that have stood the test of time. This list has pros and cons to help guide your decision-making. I recommend each person obtains lab work, an overall weight, and other metrics before and after their diet change to objectively assess their response.
Each diet listed emphasizes the reduced intake or avoidance of added sugar, refined carbohydrates, and processed foods. These diets also encourage the consumption of more real, whole foods, especially non-starchy vegetables. None of these diets require calorie counting.
The primary difference between these diets is the distribution of macronutrients (fat, protein, and calories). Some diets exclude entire food groups or categories, while others recommend moderating or reducing intake of certain foods.
The Mediterranean diet is a well-researched, sustainable dietary approach that has been ranked the #1 diet by US News and World Report. This anti-inflammatory diet emphasizes vegetables, fruits, legumes, whole grains, lean proteins, and olive oil. The Mediterranean diet has less structure compared to other diets, since different countries in the Mediterranean region eat differently.
- Improvements in cardiodiabesity, which involves metabolic health, inflammation, obesity, type 2 diabetes, and cardiovascular disease.
- Easily customizable for those with food allergies
- Able to be followed by the whole family
- Similar weight loss results compared to more restrictive, low-carb diets
- Moderately pricey due to the cost of seafood and whole food
- May require calorie tracking to ensure a calorie deficit
Originally developed in the early 1900s for children with treatment-resistant epilepsy, the ketogenic (keto) diet has been studied for its impact on a wide variety of health conditions including obesity, diabetes, cancer, dementia, Parkinson’s disease, and more. The keto diet is considered a very low-carbohydrate (5-10% of calories), high-fat diet.
- Rapid weight loss initially
- Potential for greater weight loss than low-fat or low-calorie diets
- Longer satiety
- Improvements in metabolic markers such as A1c, fasting glucose, insulin, triglycerides, and HDL cholesterol in diabetics and those overweight or obese
- Improvements in the microbiome, inflammation levels, and cardiovascular health
- Muscle mass is mostly spared during weight loss
- Requires firm restriction of carbohydrates and often net carb counting
- Some negative microbiome changes observed
- Possibility for increased intake of foods high in saturated fat, which may worsen cardiovascular disease risk for non-diabetics
- May be difficult to follow socially
- May not be sustainable for those who enjoy carbohydrates
- May be low in fiber and plant-based foods if not well-planned
A low-carb diet, also referred to as a reduced-carb diet, is less strict than a ketogenic diet and allows anywhere from 15-40% of calories from carbohydrates. Studies have used a variety of metrics to define low-carb, commonly up to 120 grams total carbs per day. Low-carb eating is more flexible than no-carb eating and emphasizes the quantity of carbs, rather than the types.
- Less restrictive than a ketogenic diet
- Documented improvements in metabolism, weight loss, triglycerides, and HDL cholesterol, which are comparable to those associated with the Mediterranean diet
- May be more socially sustainable than the ketogenic diet
- May require carb counting or tracking to maintain compliance
- Does not typically induce metabolically-beneficial ketone production
Plant-based diets may be classified as a whole food plant-based, vegetarian, vegan, or flexitarian (flexible vegetarian) diet. These diets all exclude or significantly limit animal-based foods such as meat, eggs, fish, and dairy. Well-formulated plant-based diets are very low in added sugars and processed foods, including most alternative meats. Some versions are low in fat, while others do not limit fat intake.
- High fiber intake is easily achieved
- Diet is antioxidant-rich, anti-inflammatory, and environmentally-conscious
- High-quality vegetarian and vegan diet studies show improvements in cardiometabolic risk, inflammatory markers, coronary artery disease, microbiome diversity, and blood pressure
- High carbohydrate content often ensues
- May not allow someone to meet protein needs for muscle building and maintenance
- May cause a person to experience deficiencies in choline, Vitamin B12, iron, calcium, and omega-3 fatty acids if not well-planned
The paleolithic diet’s premise is based on food that was available during the caveman era. Meat, vegetables, fruits, nuts, and seeds are encouraged while other primary food groups - such as grains, dairy, and legumes - are excluded. There is less research associated with this high-protein diet compared to others.
- Emphasis on reducing sugar and refined carb intake
- Helps improve inflammation and glucose management
- Helps meet protein needs
- Avoids grains and gluten, which may be problematic for some
- Doesn’t appear to offer superior management of blood glucose and insulin levels compared to other diets such as the Mediterranean diet
- Feels more restrictive, since many foods are excluded
- Less available research to confirm benefits
- More expensive due to meat costs
There is no “one-size-fits-all" diet. What works great for you may not work as well for others, even those in your family.
Track statistics yourself to gain an objective idea of how your body is responding.
Remember that consistency is key for long-term health change, so follow a diet that feels sustainable and also helps you meet your health goals.
Keep in mind what other lifestyle factors influence health and weight, including sleep hygiene, exercise, when you eat (fasting), and calorie reduction (how much you eat).