Keto diet: everything you need to know

The keto diet has become a frequent topic of conversation. Why? Does it offer as many health benefits as claimed? Could it sometimes be harmful? How do you follow a ketogenic diet correctly?

Read on for the answers!

 

What Is a Ketogenic or Keto Diet?

The ketogenic diet is a nutritional approach using fat as its main fuel. It is also low in carbohydrates.

 

What Does a Keto Diet Involve?

On a conventional varied diet rich in carbohydrates from cereals, tubers, pulses and fruit, glucose is the main fuel. However, the ketogenic diet relies primarily on fat, making fat the main macronutrient in this dietary pattern.

Increased fat intake combined with low carbohydrate intake on a keto diet increases ketone production. Ketone bodies form from fatty acids in liver mitochondria and provide an alternative to glucose as an energy substrate. Unlike fats, ketones cross the blood-brain barrier and fuel the brain.

A keto diet aims for nutritional ketosis, producing ketone bodies: hydroxybutyrate, acetoacetate and acetone. Nutritional ketosis is possible while consuming all three macronutrients, provided intake remains below the carbohydrate threshold that would end ketosis.

On a keto diet, glycogen stores decline. Alongside ketone production, or ketogenesis, the body can meet energy needs by producing glucose through gluconeogenesis.

 

Are There Different Keto Diets?

Yes. There are different ketogenic diets according to macronutrient distribution, preferences and goals:

• Standard ketogenic diet: low carbohydrate, moderate protein and high fat.
• Cyclical ketogenic diet: alternates high-carbohydrate periods, for example two days, with standard low-carbohydrate days.
• Targeted ketogenic diet: adds carbohydrates for intense training to support optimal performance.
• High-protein ketogenic diet: provides approximately 35% protein.
• Mediterranean ketogenic diet: restricts carbohydrates while emphasising fish, lean meat, olive oil and vegetables.
• Modified Atkins diet: developed to explore controlling refractory epilepsy through a less restrictive approach than the standard ketogenic diet.

 

 

How to Start a Keto Diet

When starting a keto diet, the aim is nutritional ketosis and associated metabolic changes and adaptations.

This requires an appropriate macronutrient distribution of carbohydrates, fats and protein.

• Meet protein requirements using the same criteria as other diets. For a keto diet aimed at fat loss, ensure at least 1.8-2 g of protein per kg body weight. For maintenance, intake may be lower. Typically, protein on keto supplies 20 to 40% of total energy.
• Keep carbohydrate intake low, around 50 grams daily, depending on body weight: 50 grams differs for someone weighing 60 kg versus 120 kg. Intake should produce ketosis and supply 5 to 20% of energy depending on the keto approach.
• The remaining energy intake should come from fat, the main fuel, approximately 45-70%.

 

Starting a ketogenic diet abruptly can be challenging. A gradual start to carbohydrate reduction may be preferable, for example 80-100 grams daily, then below 50 grams after adaptation to begin producing ketones. Check nutritional ketosis with test strips measuring ketone concentrations in urine, available from pharmacies.

Pay attention to food combinations to achieve the required macronutrient distribution. Supervision by a nutritionist helps ensure a personalised, complete diet without nutrient deficiencies that supports health and performance.

When switching to a keto diet, replace foods rich in carbohydrates, such as cereals, pulses, sugars and tubers, with foods rich in fat and/or protein, such as nuts, seeds and eggs. See “Which foods are allowed on a keto diet?” below.

This dietary pattern can be restrictive and difficult to sustain. An effective plan must support adherence and habits. Scientific benefits are of little use if the approach cannot fit someone’s life because of emotions, preferences or previous habits. Assess whether benefits outweigh drawbacks and whether it is the best strategy for the goal.

A ketogenic diet changes the predominant fuel, a process called keto-adaptation.

 

 

What Is Keto-Adaptation?

The body requires specific adaptations to use ketones instead of glucose as its main fuel. A transition period allows it to become accustomed to effective ketogenic activity, known as keto-adaptation.

Over time, a ketogenic diet produces metabolic adaptation with sustained ketosis, higher fat oxidation rates and lower carbohydrate oxidation in energy-demanding tissues such as muscle.

To become keto-adapted, the body must establish homeostasis across multiple organs to use ketones as the main fuel.

 

What Is a Keto Diet Used For?

Starting a keto diet depends on individual goals. Here are potential keto diet benefits.

 

Keto for Weight Loss

Some studies, such as Jabekk et al.1, report that equal calorie intake with different macronutrient distributions produces greater weight loss on ketogenic diets. Conclusions remain unclear, however, and some reviews suggest otherwise.

These diets burn more fat because fat is the predominant fuel. However, greater fat oxidation need not reduce body fat: this depends more on achieving a calorie deficit.

For keto-related body fat loss, early changes can be misleading. Restricting carbohydrates depletes glycogen, and each gram of glycogen stores 3-4 grams of water. Initial weight loss therefore need not represent reduced fat stores.2

Meanwhile, ketogenic diets increase satiety because fat activates intestinal mechanisms such as slower gastric emptying and increased blood concentrations of certain hormones affecting gastric emptying. This may reduce daily calorie intake.3

Overall, ketogenic diets can suit a body fat loss goal in some circumstances, but are no universal solution for losing fat.

 

Keto for Muscle Gain

The process muscle hypertrophy increases muscle size and mass. To gain muscle requires increased training volume, a positive energy balance and adequate protein for the individual.

These requirements can be met on keto, so muscle gain on a keto diet is possible. But is it optimal, equivalent or less effective?

To achieve muscle gain, muscle glycogen stores matter, but are reduced on ketogenic diets. Although brief strength sports are less glycogen-dependent, a low muscle glycogen concentration alters calcium release, essential for muscle contraction, impairing contraction and strength. Even when keto-adapted and able to use fat at higher intensities, this may be suboptimal.4

A ketogenic diet, whether maintenance-calorie or high-calorie, may therefore be suboptimal for force production and contraction.

Also, insulin is lower. Although protein stimulates it, carbohydrates have a stronger effect, potentially reducing anabolic potential.

Another challenge when seeking muscle gain on a ketogenic diet is its filling nature, making the calorie surplus needed to increase muscle mass harder to achieve.

Thus, muscle gain on keto is possible but generally less effective than on a carbohydrate-rich diet.

 

 

Benefits of a Keto Diet

Having discussed ketogenic diet effects, here are some proposed benefits.

• It may support short-term weight loss, potentially useful in sports requiring rapid pre-competition weight reduction.
• Fewer seizures in children with epilepsy. Although physiological mechanisms have not been fully investigated here, reductions in seizure numbers have been observed.
• Improved insulin sensitivity and blood glucose control.
• Greater endurance fuel efficiency. Keto-adaptation optimises fat use, reducing glucose dependence and sparing glycogen compared with carbohydrate-rich diets. This does not necessarily improve high-intensity competition performance, because metabolic flexibility and rapid glucose-derived energy production decline.

Other proposed protective benefits include the following.

 

Keto and Increased Satiety

The sensations hunger and satiety are hormonally regulated. A ketogenic diet increases leptin from white adipose tissue, supporting reduced food intake. Lower ghrelin from the stomach and neuropeptide Y are associated with less hunger.5

Some papers suggest ketones also influence ghrelin and leptin, affecting appetite through a reduced resting respiratory quotient associated with more efficient fat metabolism. 6

Ketogenic diets increase satiety because fat and protein remain in the stomach longer than carbohydrates. Also, beta-hydroxybutyrate and acetone produced in ketosis suppress appetite, potentially reducing daily calories.7

Their low glycaemic index reduces fluctuations in blood glucose. Avoiding hypoglycaemic episodes may also reduce appetite.

However, a high-fibre diet based on wholegrain carbohydrates may be even more filling than a ketogenic diet.

 

Keto Antioxidant Effects

The ketones produced during ketosis favour an antioxidant state in mitochondria, supporting inhibition of reactive oxygen species and associated lipoprotein peroxidation.

 

 

Is Keto Good for Athletes?

Many dietary strategies have emerged to improve sports performance and fitness in athletes. The ketogenic diet is proposed as an alternative to traditional carbohydrate-rich approaches in endurance sport.

To assess suitability, first understand energy pathways for muscle contraction, according to fuel and oxygen use.

 

• Phosphagen pathway: the fastest energy system, but also most limited in capacity. It supports approximately maximal-intensity effort for 10 seconds, using muscle phosphocreatine to synthesise ATP.
• Anaerobic glycolysis: slightly slower but supplying much more energy, for around 1 or 2 minutes. Limitations arise more from lactate accumulation and fatigue than fuel depletion, although fuel also matters during repeated high-intensity efforts. It uses muscle glycogen and blood glucose as fuel without oxygen, producing lactate, associated here with muscle fatigue.
• Aerobic glycolysis: uses the same substrates with oxygen. It is much slower but supports longer effort from the same fuel because using oxygen to release glucose energy avoids lactate accumulation and yields more energy per molecule. Duration depends on the pathway’s available glycogen stores in muscle and liver.
• Fat oxidation: the slowest metabolic pathway but providing proportionally the most energy, with virtually unlimited capacity relative to the others. It uses fatty acids as fuel, the preferred energy source for many tissues, including resting and fasting muscle.

 

These were described as separate pathways, but the body uses them together. Inside muscle cells, an “energy mix” operates, much like an electricity supplier.

The intensity, duration and athlete’s adaptations determine each fuel’s contribution.

The ketogenic diet limits carbohydrate, reducing glycogen stores and glucose availability.

Evidence for better sports performance is limited and depends on the sport and predominant pathways.

It may work in particular circumstances or for specific short-term goals, as discussed below.

 

 

Ketogenic Diets and Strength Athletes

The term strength means the ability to exert tension against resistance. Strength training primarily uses the phosphagen pathway, whose stores are not depleted by a ketogenic diet.

Many studies have found no loss of maximal strength on keto, but the absence of performance loss does not establish an advantage. This may apply to weightlifting and powerlifting.

When strength work becomes less maximal and set numbers increase, more glycogen is used as fuel.

If a ketogenic diet reduces glycogen, it may be less effective for muscle gain by limiting the training stimulus 8. Hormonally, a ketogenic diet is associated with lower insulin, an important anabolic hormone for muscle growth.

Some equal-calorie comparisons between a ketogenic diet and a carbohydrate-rich diet find greater carbohydrate-rich diet benefits for muscle gain. Keto can support hypertrophy but offers no advantage over a carbohydrate-rich diet. 9

You can gain strength and muscle on keto, but generally less effectively and efficiently than with sufficient carbohydrates.

 

 

Ketogenic Diets and Endurance Athletes

The activity prolonged exercise at low-to-moderate intensity relies heavily on fat oxidation. The aerobic system uses both glucose and fat.

Examples include endurance sports such as road cycling, middle- and long-distance triathlon, trail running, marathons and ultramarathons.

By minimising carbohydrate, a keto diet limits glucose use during exercise, requiring fatty acids as fuel and promoting oxidation.

The metabolism becomes more efficient at using stored fat, reducing dependence on glycogen during low-to-moderate-intensity activity.

This does not make glycogen irrelevant over long distances: it matters during intensity peaks that are higher, such as a finishing sprint in cycling.

Studies have suggested possible benefits for avoiding glycogen depletion, improving performance and delaying fatigue.

The group keto-adapted athletes can use fat as fuel more efficiently in long events, oxidising nearly twice as much as athletes on high-carbohydrate diets. This underlies interest in keto for these disciplines.

However, this need not be optimal. Most long-duration sports involve high competition intensities, making carbohydrate intake essential. In elite endurance athletes, a ketogenic diet increases fat oxidation but reduces performance because competition intensity is high.

For endurance events of short or moderate duration and higher intensity, benefits are absent. As intensity rises, glucose predominates and fat use declines.

This diet and keto-adaptation may suit non-competitive endurance activities avoiding high intensities, or low-intensity sports where carbohydrate intake is limited and preserving glycogen matters.

Benefits for high-intensity performance have not been demonstrated.

 

 

Ketogenic Diets and Team Sports

The category team sports is globally popular, including basketball, handball, rugby, volleyball, water polo, football and futsal.

Physiologically, they involve intermittent high-intensity exercise, with intense anaerobic bursts alongside moderate-to-low-intensity aerobic efforts.

These acyclical sports alternate jogging with sprints, jumps and high-intensity direction changes.

Prioritise carbohydrate intake as fuel for both aerobic and anaerobic pathways, reflecting the predominant metabolic systems and moderate-to-high intensities.

A keto diet restricts carbohydrates and reduces glycogen, making it less advisable for intermittent high-intensity sports.

 

 

Ketogenic Diets and Combat Sports

The category combat sports includes boxing, karate, judo, taekwondo, kickboxing, Muay Thai and MMA, involving intense, demanding contests.

These involve short periods at very high intensity, with punches, kicks, takedowns and blocks executed in fractions of a second, demanding substantial effort and physical and mental exertion.

The dominant systems are the phosphagen and anaerobic glycolytic pathways. The latter depends on available glycogen and dietary carbohydrates, making a ketogenic diet inadvisable during competition.

 

Which Foods Are Allowed on Keto?

A keto diet may include healthy foods such as eggs, salmon, olive oil, avocados, nuts and cheese, or less healthy choices such as processed palm fat, bacon, pork belly, lard and trans fats.

Following a keto diet does not automatically mean eating healthily. Achieving ketosis with poor-quality foods differs from a balanced approach using appropriate ingredients.

Below are foods to prioritise, moderate or exclude, seeking high nutrient density from natural, quality ingredients.

 

Foundations of a Ketogenic Diet

As keto relies mainly on protein and fat, here are options within each food group.

Meat and offal:

• Chicken
• Beef
• Liver
• Pork
• Rabbit
• Turkey
• Duck
• Cured pork shoulder
• Bacon
• Oxtail
• Lamb

 

Fish and seafood:

• Salmon
• Sardines
• Mackerel
• Herring
• Cod
• Grouper
• Trout
• Sea bass
• Hake
• Monkfish
• Turbot
• King prawns
• Prawns
• Cockles
• Mussels
• Tuna
• Squid
• Octopus
• Cuttlefish

 

Plant protein:

• Tempeh
• Soya
• Textured soya protein
• Tofu
• Dried edamame
• Heura
• Seitan
• Miso

 

Eggs

 

Fats and oils:

• Butter
• Lard
• Olives
• Cocoa
• Dark chocolate > 90%
• Olive oil
• Coconut oil
• Avocado oil
• Seed oil

 

Nuts and seeds: prioritise lower-carbohydrate varieties.

• Macadamia nuts
• Pecans
• Brazil nuts
• Walnuts
• Hazelnuts
• Almonds
• Pumpkin seeds
• Sunflower seeds
• Chia seeds
• Flaxseeds
• Sesame seeds

 

Low-carbohydrate vegetables:

Some people avoid vegetables because of their carbohydrate content. However, varieties such as leafy greens contain little carbohydrate and provide essential vitamins and minerals. Examples with few carbohydrates per 100 grams include:

• Broccoli
• Cauliflower
• Kale
• Lamb’s lettuce
• Spinach
• Chard
• Bok choy
• Alfalfa sprouts
• Rhubarb
• Brussels sprouts
• Pumpkin
• Rocket
• Red cabbage
• Lettuce
• Cucumber
• Button mushrooms
• Mushrooms
• Celery
• Garlic
• Endive
• Asparagus
• Courgette
• Aubergine
• Beetroot
• Avocado
• Onion
• Tomato
• Carrot
• Pepper

 

Full-fat dairy and preferably mature cheeses

• Manchego cheese
• Feta
• Camembert
• Goat’s cheese
• Brie
• Mozzarella
• Gouda
• Cheddar
• Blue cheese
• Kefir
• Greek or plain yoghurt

 

Spices:

Useful for adding flavour to dishes.

• Basil
• Ceylon cinnamon
• Cardamom
• Coriander
• Chilli powder
• Cumin
• Turmeric
• Bay leaf
• Nutmeg
• Oregano
• Parsley
• Sweet or hot paprika
• Pepper
• Ginger
• Rosemary
• Salt
• Thyme

 

Drinks:

• Water
• Coffee
• Tea
• Herbal infusions
• Bone broth

 

 

Foods to Moderate on Keto

Watch foods not dominated by carbohydrates but still containing meaningful amounts. Large portions or several combined may end ketosis, so quantities matter.

Vegetables and tubers:

• Cassava
• Sweet potato
• Potato
• Jerusalem artichoke
• Parsnip
• Sweetcorn
• Sun-dried tomato
• Leek

Fruit and wild berries

Prioritise lower-carbohydrate fruit such as berries.

• Raspberries
• Blueberries
• Strawberries
• Blackberries
• Lemon
• Lime
• Melon
• Watermelon
• Papaya
• Coconut

 

Nuts and dried fruit:

• Dates
• Chestnuts
• Cashews
• Pistachios
• Almonds

Dairy

Choose dairy carefully, preferably full-fat, because it contains carbohydrates alongside fat and protein.

• Whole milk
• Plain yoghurt

All these foods can fit a keto diet, but watch portion sizes.

 

What Should You Avoid on Keto?

Avoid carbohydrate-rich foods such as these examples.

Sugary and ultra-processed products:

• Soft drinks
• Fruit juices
• Pastries
• Ice cream
• Cakes
• Sweets
• Biscuits
• Nougat
• Ready-made pizzas
• Sauces

Although ultra-processed products are avoided for their carbohydrate content, healthy keto can include homemade sweet recipes such as the almond flour, egg, egg-white and peanut butter pancakes in the INDYA app.

Cereals and carbohydrate-rich foods:

• Maize flour
• Wheat flour
• Rice
• All pasta types
• Breakfast cereals
• Mashed potato
• White bread
• Wholemeal bread
• Couscous
• Jam
• Honey
• Jellies
• Fried products

Higher-carbohydrate fruit:

• Banana
• Fig
• Grape
• Quince
• Pear
• Mango
• Kiwi
• Guava
• Pomegranate
• Pineapple
• Cherry
• Coconut

Pulses:

• Peas
• Beans
• Lentils
• Broad beans
• Chickpeas

Low-fat products, often high in carbohydrate: labels such as light do not guarantee healthiness. Salt, sugars and starch may replace removed fat.

• Light biscuits
• Chocolate bars
• Products labelled keto

 

 

Alcoholic drinks:

These often contain small carbohydrate amounts, depending on the drink.

Repeated consumption offers no health benefit. People on keto who consume alcoholic drinks should watch quantities because cumulative intake increases carbohydrate consumption.

The substance alcohol is metabolised through several pathways. Chemically called ethanol, enzymes break the ethanol molecule into compounds with potentially harmful effects.

Most ethanol is broken down in the liver by ADH, converting ethanol to acetaldehyde, a highly toxic metabolite subsequently converted to acetate. Most metabolism occurs in the liver, but also in the pancreas and brain.

Excessive alcohol consumption can harm health and offers no benefit.

Alcohol on Keto

• Wine: carbohydrate content varies with fermentation.
• Spirits: distillation removes carbohydrates, but alcohol itself remains toxic.
• Liqueurs and cocktails: often very sweet and high in carbohydrate.
• Beer: malt-derived carbohydrates can disrupt ketosis, even in alcohol-free beer.

 

 

Problems with Keto

For more on keto’s drawbacks, read “Keto Diet: Side Effects and Contraindications”.

• Benefits appear against Western diets, but not against dietary patterns recommended by public institutions.
• The quality of the diet is often overlooked when only macronutrient proportions are considered.
• There is no long-term weight-loss advantage over equal-calorie alternatives.
• It is not recommended long term.

Where ultra-processed foods and fast food dominate, a keto diet that is sustainable and well planned may help by replacing junk food with healthier choices.

For example, replacing biscuits and sweetened chocolate milk with walnuts, almond drink and cauliflower bread with tuna and avocado can be a positive change.

However, keto specifies macronutrients rather than food quality. Its high fat and protein intake can encourage excessive reliance on animal products. Another example: replacing oat porridge, banana and blueberries with fried eggs and bacon may be a change for the worse.

 

Can Keto Supply All Nutrients?

With varied food choices, a keto diet can meet daily requirements, although less easily than approaches such as the Mediterranean diet.

If starting a ketogenic diet, have it planned and reviewed by your nutritionist.

Who Should Avoid Keto?

In type I diabetes, ketones rise as insulin levels fall. Inability to produce insulin can cause accumulation and ketoacidosis. Although lower-dose insulin injections may be considered in specialist care, difficult control and adverse-effect risk make keto inadvisable in this condition.

For breastfeeding women, keto is also discouraged because of breast milk’s carbohydrate needs and potential infant malnutrition. An intake of at least 50 g/day of carbohydrate is discussed as necessary to maintain milk composition. Long-term effects of keto or low-carb breastfeeding remain unknown, so precaution favours established dietary approaches for infant health.

For diet-influenced non-communicable diseases, effects depend on daily food composition. If animal foods dominate plants, cardiovascular disease and kidney-stone risk may rise. 10

People with high blood lipids, heart, kidney or bone problems should avoid this approach as described: an animal-heavy version may increase these risks and is associated with higher mortality. ¹¹

 

 

Keto Menu Ideas

Having explored the ketogenic diet and allowed foods, here are balanced menu ideas.

Keto Breakfasts

Examples for a low-carbohydrate keto breakfast include:

• Almond flour, egg-white and cashew butter pancake

Mix egg whites, baking powder, ground almonds, semi-skimmed milk and cinnamon. Cook a round pancake in a non-stick pan and serve with cashew butter.

• Almond bread sandwich with cooked ham and mozzarella

Mix ground almonds, egg, baking powder, salt and olive oil. Pour into a suitable container and microwave for 3 minutes, then fill with cheese, avocado, ham, turkey or other favourites.

• Scrambled eggs with cherry tomatoes

Cook eggs gently over low heat for a creamy texture. Serve with vegetables or cheese.

• Omelette wrap with chicken, cherry tomatoes and lettuce

Replace a wheat or maize tortilla with a thin omelette and fill similarly.

 

 

Keto Lunches

Here are some keto lunch ideas.

• Chicken breast, boiled egg, avocado, tomato and lamb’s lettuce salad

A salad is quick, healthy, refreshing, portable and easy to vary.

• Andalusian gazpacho with grilled prawns

Pair gazpacho with a protein source for a simple, healthy summer meal in 5 minutes.

• Courgette ravioli with ricotta and spinach

Slice courgette thinly, griddle and fold around ricotta and spinach to form squares. A quick, filling alternative preparation.

 

Keto Dinners

Find dinner examples in “7 Dinners for a Keto Diet”.

The app offers many keto recipes your nutritionist can add, maintaining variety and balanced nutrients while pursuing ketosis on a ketogenic diet.

 

Keto Snacks

Some quick snack ideas include:

• Nuts such as hazelnuts, almonds, macadamias, pecans and peanuts
• Sandwiches with almond bread or almond flour pancakes, as discussed under breakfast
• Homemade biscuits with egg, peanut butter and almond flour
• Cloud bread from whipped egg whites, filled with avocado and cooked ham
• Cucumber with cream cheese
• Berries such as raspberries, blackberries and strawberries

 

Keto for Medical Conditions

Since its use for childhood epilepsy became popular in 1920, researchers have explored keto for conditions such as metabolic syndrome and type II diabetes.

Keto and Epilepsy

The keto diet entered clinical use after showing benefits for epilepsy, particularly in children. Its unpredictable seizures prompted interest in the keto diet as an adjunct to medication.

It must be prescribed and monitored by a doctor with parental consent. Although mechanisms are not precisely known, keto can substantially reduce daily seizure frequency.

Adverse effects may include high blood lipids, heart problems and growth abnormalities, among others. 11 Continuous professional monitoring is therefore essential to minimise keto risks.

Keto and Type 2 Diabetes

The condition diabetes involves elevated blood glucose. A low-carbohydrate keto diet may lower glucose levels by reducing carbohydrate intake. However, diabetes also increases other risks, particularly cardiovascular disease.

Recent reviews and meta-analyses 12 suggest a keto diet may improve some markers in type 2 diabetes compared with Western diets low in whole foods.

A keto diet reduces glucose through its low carbohydrate intake 13. The prioritised metabolic pathways may contribute positively to normalising glucose and glycated haemoglobin, among other diabetes-related markers. Elevated values can cause complications such as diabetic retinopathy or nephropathy.

The main factor reducing type 2 diabetes is weight loss. Studies of even white-rice-and-fruit diets with a calorie deficit have improved management, reduced medication and sometimes produced remission 14. Benefits in some keto studies may therefore reflect the energy deficit.

Available evidence suggests the keto diet may help some cases of type 2 diabetes. More research and long-term studies are needed before broad endorsement.

Also consider cardiovascular disease, common in this population. Effects of keto on LDL and total cholesterol remain unclear here. The European Society of Cardiology has warned about cardiovascular risk from low-carbohydrate diets. 15

Positive effects on some markers do not establish this as the ideal strategy for everyone with diabetes.

 

Keto and PCOS

The condition polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-age women, with no exact known cause.

Associated disturbances include insulin resistance, altered hormone synthesis and excess body fat. Although no single treatment resolves PCOS, achieving a healthy weight through diet and exercise can improve symptoms. 16

Evidence suggests keto, specifically the Mediterranean “KEMEPHY” approach, may improve PCOS 17. Reported benefits concern the menstrual cycle, weight and cardiometabolic markers, including glucose, cholesterol and triglycerides, and hormones such as testosterone, oestradiol and progesterone.

Evidence is limited: without a comparison group, weight loss and diet effects cannot be separated. Other keto studies use major calorie restriction and poorly defined controls 18 19. Does keto itself help, or is it the weight loss?

Compare the ketogenic diet with other healthy diets matched for calories and quality in normal-weight participants to distinguish keto effects from weight loss.

 

Keto and Metabolic Syndrome

The metabolic syndrome involves abnormal cardiovascular health markers such as the lipid profile and blood pressure.

It is associated with a sedentary lifestyle and poor diet. Good eating habits and physical activity help reduce cardiovascular problems. 20 21

General management prioritises plant foods and limits animal foods such as red meat, associated with clinically meaningful reductions in cardiovascular risk 22 and blood pressure 23, improved lipids 24 and glucose. 25

A ketogenic diet can fit this definition if well planned and plant foods predominate, potentially producing similar effects to conventional approaches.

Recent systematic reviews and meta-analyses 26find keto affects metabolic syndrome markers such as glucose, triglycerides and insulin. Results vary greatly with food composition and diet duration. More research is needed on foods, duration and carbohydrate proportions before clear conclusions.

Long-term drawbacks of adaptation to ketosis remain unclear, alongside possible cardiovascular risk. Approaches with stronger evidence, such as a Mediterranean diet, are therefore preferred initially, with demonstrated benefits and long-term safety. 27

 

 

 

Keto and Cancer

The fact that cancer cells mainly use glucose has prompted research into keto. Restricting carbohydrates might reduce fuel availability and slow malignant-cell growth.

Preclinical and clinical research reports potential beneficial effects involving metabolism, gene expression and the tumour environment. Better-designed studies must clarify how ketones affect cancer-cell reproduction.

Recent meta-analyses 28and systematic reviews 29find insufficient evidence to recommend a ketogenic diet for cancer patients given current limitations.

Adequate nutrition is especially important because many patients experience malnutrition from cancer, treatment-related appetite loss and psychological difficulties. Restriction could worsen their condition. 30

 

Do You Need a Nutritionist for Keto?

A ketogenic diet is one possible approach for particular people and circumstances.

The keto diet does not suit everyone. Some find it compatible with their lifestyle, while others struggle with adverse effects of the ketogenic diet such as headaches, dizziness, nausea, vomiting, tiredness, dehydration and nutrient deficiencies.

Following a keto diet requires professional supervision and a personalised plan meeting individual needs, optimising nutrition and reducing deficiencies and adverse effects.

 

 

Keto FAQs

We finish with your frequently asked questions about the keto diet.

How Do Keto and Low-Carb Diets Differ?

A low-carbohydrate diet, or low carb, differs from a keto diet. In the former, carbohydrates supply less than 40% of daily energy. A ketogenic diet generally provides under 50 grams daily, adjusted to the person to produce nutritional ketosis. Someone 145 cm tall weighing 45 kg may require fewer carbohydrates than someone 185 cm tall weighing 135 kg.

Can Keto Be Vegan?

Yes, if complete and planned with your nutritionist. Because keto restricts carbohydrates, exclude foods rich in carbohydrate, such as cereals and pulses, and prioritise plant foods rich in fats and/or protein.

Protein needs can be met with low-carbohydrate plant proteins such as tofu, tempeh and Heura. Include nuts and seeds, fat-rich fruits such as coconut and avocado, oils, and non-starchy vegetables such as broccoli, cauliflower, cabbage, rocket, spinach, courgette and aubergine.

Use plant-based dairy alternatives such as soya or almond drinks and soya or coconut yoghurt. Berries provide antioxidants with little carbohydrate; other fruit may fit if daily totals remain appropriate.

Poor planning can compromise nutrient requirements, as with non-vegan keto, particularly iron, calcium, zinc and vitamin C. Dietitian-led planning supports completeness and avoids deficiencies.

Some low-carbohydrate diets derived from keto, such as Eco-Atkins 31using only plants, show promising health markers. However, long-term effects of keto remain insufficiently studied, so prolonged use is not recommended here.

 

 

Vegan Keto Recipe Ideas

Hungry? Try these vegan keto ideas from the INDYA app.

Tempeh with mushrooms, spinach, coconut drink and curry

For keto, omit the rice accompaniment.

Chia, green tea and raspberry pudding

Replace milk with almond or soya drink.

Curried tofu with avocado, almonds and broccoli

Omit quinoa and replace raisins with avocado, for example.

 

The app offers 100% keto recipes for enjoyable, straightforward planning with required nutrients, supervised by your sports nutritionist.

Unsure where to start? Explore our subscription options and let us begin.

Written by Jose Revert Valls, Pablo Hernández and Sonia Martínez Huesca. Reviewed by Rubén Ballesteros and Marta Aguilar.

References

1. Olsson, K.E., & Saltin, B. (1970). Variación en el agua corporal total con cambios en el glucógeno muscular en el hombre. Análisis Acta Physiol, 80(1): 11–8.
2. Martín-Moraleda, E., Delisle, C., Collado-Mateo, D., & Aznar, S. (2019). Cambios en la pérdida de peso y la composición corporal con dieta cetogénica y práctica de actividad física: revisión narrativa, metodológica y sistemática. Nutr Hosp, 36(5): 1196-1204. 
3. Bejarano-Carrillo, J.A., Yago-Torregrosa, M.A., Mañas-Almendros, M., López-Millán, M.B., Martínez-Burgos, M.A., & Victoria-Muñoz, E.M. (2015). Macronutrientes, ingesta de alimentos y peso corporal; papel de la grasa. Nutr Hosp, 31(1): 46-54. 
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