Comparing Diets

There are several different dietary approaches, each with its own food choices, nutritional composition and practical considerations. This page explains eight approaches: Paleo, Keto, Carnivore, Animal-Based, Ketovore, Adjusted Mediterranean-Style, Vegetarian and Vegan.

We outline the main characteristics of each approach, potential benefits, practical and nutritional considerations, and what current research says about athletic performance, muscle strength and muscle mass. The information is intended to help you understand the differences between these approaches; it does not mean that we recommend or prescribe every approach for every individual.

The suitability of any dietary approach depends on the individual. To learn more about how we consider food preferences, individual tolerance, nutrition and strength training when preparing personalised programmes, read Our Approach to Personalised Nutrition and Strength Training.

1. Paleo Diet

Overview

The Paleo diet is based on a modern interpretation of the foods available to people in prehistoric times. It generally includes meat, fish, eggs, vegetables, fruit, nuts and seeds, while excluding grains, legumes and dairy products. Added sugars and highly processed foods are also commonly avoided.

Paleo is not automatically a ketogenic or very-low-carbohydrate diet. The amount of carbohydrate depends largely on the quantities of fruit and starchy vegetables included.

Potential Benefits

Paleo provides a clear framework for food selection and removes several food groups, including grains and legumes. Depending on the foods chosen, it can also reduce reliance on highly processed foods and added sugars.

Research has investigated Paleo-style diets in relation to body weight, blood glucose and blood lipid levels. Results vary between studies.

Practical Considerations

Paleo allows a range of animal foods, including beef, pork, lamb, chicken, turkey and other poultry, fish, seafood and eggs, alongside vegetables, fruit, nuts and seeds. The usual Paleo approach excludes grains, legumes and dairy products.

Fat sources can include beef tallow, lard, duck fat, olive oil, coconut oil and avocado oil. Butter and ghee are excluded in stricter versions because they are derived from dairy, although some variations allow ghee.

A lower-carbohydrate version can limit the quantities of fruit and starchy vegetables. The choice of foods depends on the individual's preferences and goals.

Nutritional Considerations

The nutritional composition of a Paleo diet depends on the foods selected. Meat, fish and eggs provide protein and a range of essential nutrients. Fruit and vegetables provide different vitamins, minerals and plant compounds.

Because traditional Paleo excludes dairy products, calcium intake deserves particular attention. The variety of foods included also influences the intake of other nutrients.

Research Perspective

Research into Paleo-style diets has examined metabolic outcomes, including blood glucose and blood lipid measurements. Studies differ in their participants, dietary definitions, duration and outcomes. Findings from one version of Paleo do not necessarily apply to every variation.

Athletic Performance, Muscle Strength, and Muscle Mass

There is limited research directly examining Paleo diets in athletes. An eight-week study involving 15 professional handball players compared a Paleo group with a control group. The study reported changes in body composition in both groups, but it did not establish a clear performance advantage from following Paleo. Its small sample size also limits the conclusions that can be drawn. [17]

There is currently no sound basis for claiming that Paleo produces better athletic performance or greater muscle growth than other suitable dietary approaches.

As with other diets, training quality, sufficient energy intake, adequate protein and recovery are important when working towards improvements in strength and muscle mass.

2. Ketogenic (Keto) Diet

Overview

The ketogenic diet, commonly called Keto, is a very-low-carbohydrate approach designed to encourage the body to produce ketones. This metabolic state is known as nutritional ketosis.

Keto generally restricts carbohydrate more strictly than a standard low-carbohydrate diet. It is defined primarily by carbohydrate restriction, not by eating only animal foods.

A ketogenic diet can include meat, fish, eggs, selected dairy products, oils, nuts, seeds and low-carbohydrate vegetables.

Potential Benefits

Ketogenic diets have been researched in relation to energy metabolism, appetite, body weight and metabolic health.

One established medical application is dietary therapy for some people with drug-resistant epilepsy. This treatment requires medical supervision. [8]

Research has also examined ketogenic diets in relation to blood glucose regulation, body weight and blood fats.

Practical Considerations

Keto requires close attention to carbohydrate intake. Foods such as bread, pasta, rice, potatoes and sugar are substantially reduced or excluded.

Common choices include beef, pork, lamb, chicken, turkey and other poultry, fish, seafood and eggs. Dairy products such as cheese and cream may also be included, depending on personal preference and tolerance. Selected low-carbohydrate vegetables, nuts and seeds may also be included.

Cooking fats can include beef tallow, lard, butter, ghee, duck fat, olive oil, avocado oil and coconut oil. The choice depends on personal preference, food tolerance and the type of meal being prepared.

Some people experience temporary symptoms when first reducing carbohydrate intake. These can include headaches, tiredness, dizziness, changes in bowel habits or muscle cramps. The transition and its effects can differ between individuals.

Nutritional Considerations

Food quality remains important. Protein intake, the types of dietary fats consumed and the selection of foods all influence the nutritional composition of a ketogenic diet.

Because Keto substantially reduces carbohydrate intake, food choices should be planned with attention to vitamins, minerals and overall nutritional adequacy.

Research Perspective

Ketogenic diets have been investigated in several areas, including epilepsy, body weight and metabolic health. The strength of the evidence differs between applications.

The medical use of ketogenic dietary therapy for certain forms of epilepsy is established, but findings from that application should not be treated as evidence for every use of Keto.

Athletic Performance, Muscle Strength, and Muscle Mass

Research does not establish that Keto improves strength or muscle growth compared with diets that include more carbohydrate.

A 2025 systematic review and meta-analysis examined 33 studies of ketogenic diets and outcomes including muscle mass, strength, aerobic capacity and endurance. It found no significant overall advantage for Keto in muscle mass, strength or power. Changes in fat-free mass should not automatically be interpreted as changes in muscle tissue, because fat-free mass includes other components of the body. [18]

A separate meta-analysis of 18 studies involving trained adults found that carbohydrate-rich diets generally produced more favourable estimates for time-trial performance and one-repetition maximum strength. The authors concluded that Keto was not suitable for enhancing strength or high-intensity cyclic performance, although it may be useful for reducing body weight and fat mass. [19]

A smaller randomised controlled trial involving trained men undertaking resistance training also found no clear advantage for Keto in improving body composition. [20]

These findings do not mean that people cannot train or build muscle while following Keto. They mean that current research does not support claiming that Keto produces better athletic performance or muscle growth than diets that provide more carbohydrate.

3. Carnivore Diet

Overview

The Carnivore diet is based exclusively on animal foods and excludes plant foods.

Common choices include beef, pork, lamb, chicken and other poultry, fish, seafood, eggs and animal fats. Some people also include dairy products, while others prefer to avoid them. Animal fats may include butter, tallow and other fats obtained from animal foods.

There are different ways to follow the diet. Food choices depend on personal preferences, tolerance and the particular approach someone follows.

The diet is more restrictive than other approaches because it removes plant foods entirely.

Potential Benefits

People following Carnivore report changes in digestion, skin problems, energy levels, joint and muscle symptoms, body weight and general wellbeing. Some describe substantial improvements in long-standing symptoms.

The simplicity of the diet appeals to people who prefer a clearly defined selection of foods. Removing a large number of foods can also help some individuals identify whether particular foods are associated with unwanted symptoms.

Animal foods provide concentrated sources of protein and several essential nutrients.

Practical Considerations

The Carnivore diet excludes vegetables, fruit, grains, legumes, nuts and seeds.

Food selection can include different cuts of beef, pork, lamb, chicken, turkey and other poultry, fish, seafood and eggs. The amount of fat and protein varies between foods and cuts of meat. Dairy products are included by some people but excluded by others.

Animal fats, such as beef tallow, lard, butter, ghee, lamb fat and duck fat, may be used for cooking or added to meals. Bacon fat and the natural fat attached to meat are also options.

A varied selection of suitable animal foods is important because different foods provide different nutrients.

Nutritional Considerations

The nutritional composition of a Carnivore diet depends on the foods selected. Lean and fatty cuts of meat provide different balances of protein and energy. Fish and seafood contribute nutrients that are not present in the same amounts in every type of meat. Eggs and dairy products, when included, also contribute different nutrients.

Some nutrients, including calcium, iodine and vitamin C, require particular consideration depending on the foods included. Nutritional planning should reflect the actual food choices rather than assuming that every version of the diet has the same composition.

Research Perspective

Research into Carnivore diets remains limited. A published survey of 2,029 adults following a Carnivore diet documented self-reported improvements in overall health, wellbeing and various medical conditions. The study also reported high levels of low-density lipoprotein cholesterol among some participants. Because the survey relied on participants' reports and did not use a controlled comparison, it cannot establish that the diet caused the reported improvements. [9]

A 2026 review of the available human research found only nine studies that met its inclusion criteria. The authors identified limitations in the quantity and quality of the evidence, as well as potential nutritional and cardiovascular concerns. [10]

These publications provide an early picture of the available research, but larger and longer-term studies are needed.

Athletic Performance, Muscle Strength, and Muscle Mass

There is currently no sound basis for claiming that the Carnivore diet improves athletic performance, strength or muscle growth.

A 2026 review examining Carnivore and Animal-Based diets in sport found that direct evidence in athletes was very limited. The authors noted the lack of well-controlled, long-term intervention studies that could establish whether these diets improve sport-specific performance or training adaptations. [21]

This is a lack of sufficient evidence for a performance advantage, rather than proof that someone cannot exercise or build muscle while following the diet.

Resistance training, sufficient energy intake, adequate protein and recovery remain important. The available research does not establish that excluding all plant foods provides an additional advantage for these outcomes.

4. Animal-Based Diet

Overview

An Animal-Based diet places animal foods at the centre of the diet but is not necessarily limited to animal foods.

Depending on the version followed, it may include meat, fish, seafood, eggs, dairy products and selected plant foods, such as fruit or honey.

Animal-Based eating is not automatically ketogenic or low-carbohydrate. Some versions include substantial amounts of carbohydrate from fruit and honey, while others restrict these foods more closely.

The distinction is important: Carnivore excludes plant foods, whereas Animal-Based approaches may include selected plant foods alongside animal foods.

Potential Benefits

Animal-Based approaches emphasise foods that provide concentrated sources of protein and essential nutrients. Meat, fish, eggs and dairy provide different combinations of vitamins, minerals, fats and amino acids.

Some people prefer this approach because it places familiar animal foods at the centre of meals while allowing more flexibility than a strict Carnivore diet.

The inclusion of selected additional foods can make the approach suitable for people who do not wish to exclude every plant food.

Practical Considerations

There is no single standard definition of Animal-Based eating. The foods included can vary considerably.

Common choices include beef, pork, lamb, chicken, turkey and other poultry, fish, seafood, eggs and dairy products. Depending on the version followed, selected plant foods such as fruit and honey may also be included.

Fat sources can include beef tallow, lard, butter, ghee, lamb fat and duck fat. Some versions also use coconut oil. The choice of fats depends on the particular approach and the foods being prepared.

Some versions include fruit and honey more freely, while others limit these foods according to the individual's carbohydrate preferences. Dairy products may also be included or excluded.

The particular foods and quantities should be clearly defined when following this approach.

Nutritional Considerations

The nutritional composition depends on the foods selected. Meat, fish, eggs and dairy provide different nutrients, while fruit and other selected plant foods add their own carbohydrates, vitamins, minerals and other compounds.

The inclusion of fruit or honey can substantially change carbohydrate intake. This is particularly relevant for people who also want to maintain nutritional ketosis.

Research Perspective

Research specifically examining Animal-Based diets as a distinct dietary pattern is limited. Findings from Carnivore research cannot automatically be applied to Animal-Based eating because the permitted foods may differ.

More direct research is needed to establish the longer-term effects of different Animal-Based approaches.

Athletic Performance, Muscle Strength, and Muscle Mass

There is currently no sound basis for claiming that Animal-Based diets improve athletic performance, strength or muscle growth.

The 2026 review examining Carnivore and Animal-Based diets in sport found that direct research on these dietary patterns in athletes is insufficient to establish a performance advantage. It is important not to treat evidence from studies of individual animal foods or high-protein diets as proof that the complete Animal-Based dietary pattern improves athletic performance. [21]

An Animal-Based diet can provide protein and energy from animal foods, but the amount and balance of carbohydrate, fat and protein depend on the foods selected. More direct research is needed before claims of superior muscle growth or athletic performance can be supported.

5. Ketovore Diet

Overview

The Ketovore diet combines elements of the ketogenic (Keto) diet and the Carnivore diet.

It focuses mainly on animal foods, such as meat, fish, eggs and animal fats, while allowing selected low-carbohydrate plant foods if desired.

Like Keto, Ketovore aims to keep carbohydrate intake very low so that the body can produce ketones for energy. Like Carnivore, it places a strong emphasis on animal foods.

Unlike a strict Carnivore diet, Ketovore may include small amounts of selected vegetables or other low-carbohydrate plant foods.

There is no single standard definition of Ketovore, so the foods included and the amount of carbohydrate consumed can vary.

Potential Benefits

Ketovore may appeal to people who prefer to base their diet on animal foods but do not want to exclude all plant foods.

The approach combines a strong emphasis on animal foods with the carbohydrate restriction associated with Keto. It offers a framework for people who want to maintain a very-low-carbohydrate intake while retaining some flexibility in food choices.

Practical Considerations

The main practical consideration is deciding which foods are included and how much carbohydrate the plan allows.

Common choices include beef, pork, lamb, chicken, turkey and other poultry, fish, seafood, eggs and animal fats. Some people also include dairy products such as cheese, cream and butter. Selected low-carbohydrate vegetables may be included in smaller quantities, depending on personal preference and carbohydrate goals. Nuts, seeds and other low-carbohydrate plant foods may also be included.

Animal fats can include beef tallow, lard, butter, ghee, lamb fat and duck fat. Some people also use olive oil, avocado oil or coconut oil, depending on their food choices and approach.

Some people include selected low-carbohydrate vegetables, while others prefer to keep plant foods to a minimum. The amount of carbohydrate matters when the aim is to maintain nutritional ketosis.

Nutritional Considerations

The nutritional composition of Ketovore depends on the balance of animal foods and selected plant foods.

Meat, fish, eggs and animal fats provide protein, energy and a range of essential nutrients. Additional foods should be considered in relation to carbohydrate intake, individual tolerance and nutritional requirements.

A very restricted selection of foods makes nutritional planning particularly important.

Research Perspective

Research specifically examining Ketovore as a separate dietary approach is currently very limited.

Research on Keto or Carnivore cannot automatically be treated as evidence for Ketovore because the diets may differ in their food choices and nutritional composition.

Athletic Performance, Muscle Strength, and Muscle Mass

There is currently no sound basis for claiming that Ketovore improves athletic performance, strength or muscle growth.

The research available on Keto and Carnivore does not directly establish the effects of combining these approaches. The findings from studies of either diet cannot simply be transferred to Ketovore.

Until controlled studies examine Ketovore itself, claims that it provides a particular advantage for athletic performance or muscle development remain unproven.

6. Adjusted Mediterranean-Style Diet

Overview

Our adjusted Mediterranean-style diet differs from a traditional Mediterranean diet.

Traditional Mediterranean-style eating can include substantial amounts of whole grains, legumes, fruit and other carbohydrate-containing foods. Our adjusted approach places greater emphasis on reducing overall carbohydrate intake, added sugars and starchy foods.

The plan is adapted to your goals and food preferences, with attention to suitable sources of protein and fat and an emphasis on minimally processed foods.

Potential Benefits

An adjusted Mediterranean-style approach may appeal to people who prefer a broader range of foods but want to reduce their intake of sugar and starch.

Depending on the foods selected, it can include fish, meat, eggs, dairy products, olive oil, selected vegetables, nuts and other foods that fit the chosen level of carbohydrate restriction.

Traditional Mediterranean-style diets have been studied in relation to cardiovascular health. [11]

Practical Considerations

The main difference between our adjusted approach and a traditional Mediterranean diet is the amount and type of carbohydrate-containing foods included.

Food choices may include beef, pork, lamb, chicken, turkey and other poultry, fish, seafood, eggs, dairy products, selected vegetables and nuts. Olive oil is a principal fat source. Butter, ghee and animal fats such as tallow or duck fat may also be used, depending on the individual's preferences and the particular plan.

Traditional versions may include substantial quantities of grains, legumes and fruit. Our adjusted approach can reduce or limit these foods according to the individual's preferences and carbohydrate goals.

Nutritional Considerations

The nutritional composition depends on the foods selected and the degree of carbohydrate restriction.

Protein sources, dietary fats, vegetables and other foods should be considered together. Individual food tolerance is also relevant when choosing which foods to include.

Research Perspective

Traditional Mediterranean-style diets have been studied extensively, including in cardiovascular research. Our adjusted Mediterranean-style diet is a tailored, lower-carbohydrate approach and is not identical to the traditional dietary patterns examined in those studies. [11]

Athletic Performance, Muscle Strength, and Muscle Mass

Research into traditional Mediterranean-style diets and athletic performance has produced mixed findings. A 2024 systematic review examined studies involving athletes and non-professional participants. It found some favourable results, but the studies differed in their participants, methods and outcomes. [22]

A 2025 systematic review and meta-analysis examined Mediterranean-style diets in elite and competitive athletes. It did not establish a clear overall improvement in athletic performance. The authors also identified limitations in the available studies. [23]

These studies examined traditional Mediterranean-style diets, not the adjusted lower-carbohydrate approach described here. Their findings therefore cannot establish that our adjusted version improves athletic performance, strength or muscle growth.

7. Vegetarian Diet

Overview

A vegetarian diet excludes meat, poultry and fish but may include foods such as eggs, milk, cheese, yoghurt and other dairy products. The exact foods included depend on the type of vegetarian diet followed.

Some vegetarians eat eggs and dairy products, while others exclude one or both. A lacto-vegetarian diet includes dairy products but excludes eggs. An ovo-vegetarian diet includes eggs but excludes dairy products. A lacto-ovo vegetarian diet includes both.

Vegetarian diets can contain a wide range of foods, including vegetables, fruit, grains, beans, lentils, nuts, seeds, eggs and dairy products.

Potential Benefits

A vegetarian diet can provide a varied selection of foods and can be adapted to different preferences and nutritional goals.

Eggs and dairy products can provide complete protein and important nutrients. Beans, lentils, nuts, seeds and other plant foods also contribute protein, fibre, vitamins and minerals.

A well-planned vegetarian diet can provide the energy and nutrients needed for everyday activities and exercise.

Practical Considerations

The foods included depend on the individual's chosen version of vegetarian eating.

Protein sources may include eggs, milk, yoghurt, cheese, beans, lentils, chickpeas, peas, nuts, seeds, tofu and other soy products.

People who avoid meat and fish need to consider how they obtain nutrients commonly supplied by these foods. Iron, vitamin B12, iodine, zinc, calcium and omega-3 fatty acids deserve particular attention, depending on the foods included.

The amount and quality of protein in a vegetarian diet depend on the combination and quantities of foods eaten. Including a variety of protein sources can help provide the essential amino acids required by the body.

Vegetarian diets can include a substantial amount of carbohydrate from foods such as grains, beans, lentils, fruit and starchy vegetables. Rather than automatically reducing these foods, the nutrition and exercise programme can be adapted to the individual's dietary choices, energy intake, training requirements and recovery.

Nutritional Considerations

A vegetarian diet can meet nutritional needs, but food selection matters.

Vitamin B12 is naturally present mainly in animal-derived foods. People who include eggs and dairy may obtain some B12 from these foods, but the amount depends on how much they consume. Fortified foods or supplements may be needed if dietary intake is insufficient.

Iron is another nutrient to consider. Plant foods provide non-haem iron, which is absorbed differently from the haem iron found in meat and seafood. The overall diet and food combinations influence iron absorption. [5]

Iodine intake can also be low in some vegetarian diets, particularly when dairy products and seafood are excluded. The amount of iodine in foods varies, so suitable sources need to be considered.

Research Perspective

Research comparing plant and animal protein has examined outcomes such as lean mass, muscle strength and muscle protein synthesis. Results vary according to the protein sources, participants and study design. Some analyses have found small differences in muscle mass, while others have found no significant difference in strength. [6, 7, 25]

The evidence does not support treating all plant proteins as identical. Protein source, amino-acid composition, digestibility and total intake all matter.

Athletic Performance, Muscle Strength, and Muscle Mass

A well-planned vegetarian diet can support resistance training and muscle development when it provides sufficient energy, protein and essential nutrients.

A 2025 systematic review and meta-analysis of randomised controlled trials found no significant overall difference in muscular strength between plant-based and omnivorous diets. The studies included different plant-based dietary patterns, so the findings should not be interpreted as proof that every vegetarian diet produces identical results. [24]

Research comparing plant and animal protein has found some differences in muscle mass outcomes, but no significant overall difference in muscle strength or physical performance in the relevant pooled comparisons. [25]

The practical priority is to consume enough total protein and energy, include suitable protein sources and follow a consistent resistance-training programme. A vegetarian diet does not automatically prevent muscle growth, but its composition needs to be considered.

8. Vegan Diet

Overview

A vegan diet excludes all animal-derived foods, including meat, poultry, fish, seafood, eggs, milk, cheese, yoghurt and other dairy products.

It is based on plant foods such as vegetables, fruit, grains, beans, lentils, peas, nuts, seeds and plant-based alternatives to animal products.

People choose vegan diets for different reasons, including personal preferences, ethical considerations, animal welfare, environmental concerns or other individual motivations.

Potential Benefits

A vegan diet can include a wide range of plant foods and can provide carbohydrates, protein, fats, vitamins, minerals and fibre.

Foods such as beans, lentils, chickpeas, peas, tofu, tempeh, nuts and seeds can contribute protein. Whole grains and vegetables can provide additional nutrients and energy.

A varied vegan diet can be adapted to different food preferences and activity levels.

Practical Considerations

Because a vegan diet excludes all animal foods, it requires particular attention to nutrients that are naturally concentrated in meat, fish, eggs and dairy products.

Protein sources may include soy products, beans, lentils, chickpeas, peas, nuts, seeds and other plant-based foods. Some people also use fortified plant-based products.

Plant proteins differ in their essential amino-acid content and digestibility. Including a variety of protein sources and sufficient total protein is important, particularly for people undertaking regular strength training.

Vegan diets can include a substantial amount of carbohydrate from foods such as grains, beans, lentils, fruit and starchy vegetables. Rather than automatically reducing these foods, the nutrition and exercise programme can be adapted to the individual's dietary choices, energy intake, training requirements and recovery.

Nutritional Considerations

Vitamin B12 requires particular attention because unfortified plant foods are not reliable sources. Vegans need a dependable source of B12 through fortified foods, supplements or both. A systematic review and meta-analysis found lower vitamin B12 status and a greater risk of functional B12 deficiency among vegan adults compared with non-vegans. [15]

Iodine also deserves attention. Some vegan diets may provide insufficient iodine, depending on the foods selected and whether reliable iodine sources are included. Iodine is required for the production of thyroid hormones. [16]

Other nutrients to consider include iron, calcium, zinc, selenium, vitamin D and long-chain omega-3 fatty acids. The amount available depends on the foods selected, food preparation and the overall composition of the diet.

Research Perspective

Research comparing plant and animal protein has found that the results can differ according to the type of plant protein and the outcome being measured. Some studies report a small advantage for animal protein in certain muscle-mass measurements, while other comparisons find no significant difference in muscle strength or physical performance. [6, 7, 25]

These findings do not mean that a vegan diet cannot support muscle development. They highlight the importance of protein quantity, quality and overall nutritional planning.

Athletic Performance, Muscle Strength, and Muscle Mass

A vegan diet can support strength training and muscle development when energy and protein intake are sufficient and the diet is planned carefully.

A 12-week study compared habitual vegans and omnivores undertaking resistance training while consuming protein-matched diets. Both groups achieved similar increases in muscle and strength measurements. The study suggests that a well-planned plant-based diet can support resistance-training adaptations when protein intake is adequate, although its relatively small sample means the findings should not be treated as conclusive for every athlete. [14]

A 2025 systematic review and meta-analysis found no significant overall difference in muscular strength between plant-based and omnivorous diets. [24] Another meta-analysis comparing plant and animal protein found no significant overall difference in muscle strength or physical performance, although some muscle-mass outcomes favoured animal protein over certain non-soy plant proteins. [25]

These findings indicate that vegan diets can support muscle development, but attention to total protein, suitable protein sources, energy intake, vitamin B12, iodine and other relevant nutrients is important.

Important Medical Information

Claudia and Michael are not medical practitioners or registered dietitians. Our programmes provide nutrition and exercise guidance based on personal experience and are not a substitute for medical diagnosis or treatment.

People with diagnosed medical conditions or taking medication should discuss significant dietary changes with their healthcare professional. This is particularly important for people taking diabetes medication before substantially reducing carbohydrate intake, as medication adjustments may be necessary.

Scientific References

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