Diet Atlas
Not all diets are created equal, so this page brings together evidence-based reviews of the most popular diets out there. Each diet is assessed by the same criteria: health benefits, nutrition, sustainability, evidence base, and safety. Each article goes through the rules of the diet, what mealtimes look like, the pros, cons, and who each diet suits (and doesn't): find the one that fits you.
TLC Diet: A Review ★★★★☆
Ketogenic Diet: A Review ★★★☆☆
Low-Fat Diets: A Review ★★★☆☆
Each diet is assessed on the following criteria: health benefits, nutritional quality, weight loss potential, long-term sustainability, strength of the supporting evidence, and safety. Each criterion is scored out of 5 then we calculate an 'overall' median score for the diet. Scores reflect the current body of evidence and are intended as a comparative guide — not a definitive verdict. A diet that scores well on weight loss may score lower on sustainability, so it's worth reading the full review rather than relying on the overall score alone.
The Mediterranean diet consistently receives the strongest overall support in peer-reviewed research, with robust evidence for cardiovascular health, weight loss, and long-term adherence. The DASH diet is also well-supported, particularly for blood pressure and metabolic health. That said, the "best" diet depends on your individual health goals, preferences, and medical history — no single diet is optimal for everyone.
Most popular diets are safe for healthy adults in the short term, but some do carry meaningful risks for certain groups or if they are followed for an extended period of time. Very low-calorie diets, extreme elimination diets, and approaches that severely restrict food groups can lead to nutritional deficiencies, disordered eating patterns, or complications for people with specific health conditions. Our reviews flag any safety concerns. But if you have a medical condition or are taking medication, speak with your doctor or a registered dietitian before making major dietary changes.
The term "diet" is often used to describe a temporary, goal-oriented eating plan. A "way of eating" (or dietary pattern) refers to long-term habitual food choices. Increasingly, research supports the view that sustainable dietary patterns (rather than short-term changes) are what drive lasting health outcomes. The reviews on this page cover both types.
No. Most nutrition research points not to specific named diets, but to broad dietary 'patterns': eating plenty of vegetables, fruit, legumes, wholegrains, and quality protein; limiting ultra-processed foods, added sugars, and excess sodium; and maintaining a reasonable calorie balance. Named diets can be a useful structure for people who benefit from clear rules, but they are not a prerequisite for good nutrition.
High Protein Diet: A Review ★★★☆☆
Ultra-Processed Food Diet: A Review ★☆☆☆☆
Western Diet: A Review ★★☆☆☆
Mediterranean Diet: A Review ★★★★★
Okinawa Diet: A Review ★★★★☆
DASH Diet: A Review ★★★★★
Carnivore Diet: A Review ★★☆☆☆
Atkins Diet: A Review ★★★☆☆
Blue Zone Diet: A Review ★★★★☆
THERAPEUTIC DIETS
Diets used to manage symptoms or support specific medical needs, rather than broad general-health diets
HOW WE SCORE EACH DIET
Methodology
Each diet is individually scored across five different domains on a 1-5 Likert scale, and a rounded median is calculated as an 'overall' score for the diet. Individual domain scores are available at the bottom of each article.
- Health benefits of the diet
- Nutrient content of the diet
- Weight loss and weight control
- Feasibility: How easy it is to follow.
- Safety profile and adverse events
We only score diets that are used or promoted for general adoption, regardless of their original purpose. Specialist therapeutic diets that are designed solely to treat specific health conditions or medical needs are reviewed, but not scored under the rubric. Diets that have therapeutic use but have been widely adopted beyond their original clinical context are scored. Examples include the gluten-free, ketogenic, very-low-calorie, MIND, DASH, and TLC diets. Their therapeutic efficacy is still discussed in the article, but may not be reflected in the overall score.
Overall Score
Overall, the evidence is strong, and the diet is highly recommended for general adoption; it consistently shows benefits across multiple outcomes and is broadly sustainable with minimal trade-offs.
Overall, the evidence is good and the diet is suitable for most people; the majority of dimensions are positive, with only minor trade-offs or caveats in one or two areas.
Overall, the evidence is mixed, and the diet is recommended only with caution; it may be suitable for specific populations or short-term use, but is not broadly recommended without consideration of individual circumstances.
Overall, the diet offers limited benefits with notable drawbacks; practical and safety concerns limit its suitability for most people and it is not broadly recommended.
Overall, the diet performs poorly across all dimensions assessed; the evidence consistently points to harm or serious sustainability failures and adoption should be actively discouraged without specialist medical oversight.
Health Benefits
Strong, consistent health benefits across two or more major outcomes, supported by three or more independent meta-analyses or five or more high-quality randomised controlled trials showing reduced disease risk or mortality.
Clear health benefits across one or more major outcomes, supported by two or more high-quality randomised controlled trials or at least one meta-analysis with consistent results; minor inconsistencies may be present in a small number of studies.
Evidence of benefit is limited to short-term outcomes or biomarker improvements rather than clinically meaningful disease endpoints; available studies are often small, short, or lack independent replication.
Evidence is inconsistent or low quality, with no reliable demonstration of reduced disease risk or improved health outcomes; findings are frequently contradictory or limited to poorly controlled research.
There is credible evidence of harm or absence of meaningful benefit; the diet is associated with increased disease risk, adverse metabolic outcomes, or other measurable negative health effects.
Nutrition
The diet meets over 90% of the recommended daily allowance for over 90% of essential nutrients, includes all major food groups, and requires no supplementation.
The diet meets over 80% of the recommended daily allowance for over 80% of essential nutrients; no more than one supplement is likely needed to address minor gaps.
The diet has moderate nutritional adequacy but shows gaps in one or two essential nutrients or excludes at least one major food group, which may require adjustment or supplementation over time.
The diet is likely to result in two or more nutrient deficiencies or requires exclusion of multiple major food groups, posing a meaningful risk of nutritional inadequacy.
It involves severe nutritional restriction or promotes unsafe intake levels — such as very high sodium or saturated fat, or critically low carbohydrate or fibre — inconsistent with established nutritional safety thresholds.
Bodyweight
Multiple high-quality studies report measurable weight loss of over 5%, sustained beyond 12 months in overweight or obese participants. Those who follow the diet are very likely to maintain a healthy body weight over time.
Studies report moderate, sustained weight loss of around 5% over six to twelve months with reasonable adherence in overweight or obese people. Those who follow the diet are likely to maintain a healthy body weight over time.
Short-term weight loss of over 3% has been observed in some studies, but maintenance beyond six months is poor and regain is common in overweight or obese people. Those who follow the diet may be able to maintain a healthy body weight over time.
Weight loss outcomes are minimal, trivial, or inconsistent across studies, with average losses of less than 3%; dropout rates are high, limiting the reliability of even short-term findings. Those who follow the diet are unlikely to maintain a healthy body weight over time.
The diet is ineffective for achieving and maintaining a healthy body weight and is associated with weight cycling, significant regain beyond baseline, or short-term losses that are not sustained. Those who follow the diet are very unlikely to maintain a healthy body weight over time.
Feasibility
The diet is accessible, flexible, low cost, and socially adaptable, with studies reporting over 70% adherence beyond six months.
Adherence rates of 50–70% are reported; cost and planning demands are moderate.
Adherence rates of 30–50% are reported; cost, social barriers, or dietary restrictiveness present meaningful challenges to long-term adoption.
Adherence rates are below 30%; the diet is often costly, complex, or socially limiting.
Adherence rates are below 15%; the diet is frequently described as socially isolating, financially demanding, or incompatible with normal daily life.
Safety
It is safe for most people, broadly aligns with dietary guidelines, and has no adverse effects.
The diet is generally safe for healthy adults, with only minor reversible effects and no significant safety concerns.
The diet is generally safe but may pose risks for certain populations, including people with diabetes, kidney disease, or other vulnerable populations with pre-existing conditions.
Documented adverse effects have been reported, nutritional deficiencies are common and well-evidenced, and medical supervision is recommended.
It carries a high risk of harm, with documented links to measurable health damage, nutritional deficiency, or elevated risk of disordered eating.
Our Editorial Approach
Alphabet Guides publishes practical evidence-based content using trustworthy, peer-reviewed research: information you can actually use. Learn more About Us and our Editorial Standards.