Keto Diet: 8 Health Benefits, What to Eat & Avoid (plus Meal Plan)

The keto diet  consists of prioritizing lean meats and healthy fats and drastically reducing carbohydrate intake. Patients following a keto diet are encouraged to foods like nuts, lean cuts of meats, fruits and veggies, and to avoid eating foods that are carb-heavy, like bread and rice. This triggers the body to use its own fat stores as a source of energy, instead of the carbohydrates that come from food. 

This diet can be a great alternative for those wishing to lose weight, as long as it is supervised by a registered dietitian. It can also be prescribed to help with the management and prevention of epileptic seizures. Studies are currently being done to support this diet as a complement to cancer treatment, as cancer cells have been studied to feed off of carbohydrates

It is important to highlight that this diet should be approved by your doctor and supervised by a registered dietitian. A health care professional can complete a thorough nutritional assessment to evaluate whether you are a good candidate for this diet.

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How it works

The ketogenic diet involves a drastic reduction of carbohydrates, which will make up only 10 to 15% of total daily calories. However, this quantity may vary according to your health condition, how long the diet will last, and your dietary goals.  

To compensate for the reduction in carbohydrates, you will need to significantly increase your intake of fat. This means eating foods like avocado, coconut, seeds, olive oil, peanuts, chestnuts, walnuts, and almonds. The quantity of protein in your diet should also increase until it makes up 20% of daily calories. It is, therefore, necessary that you eat meat, chicken, or fish at lunch and dinner and that you have eggs and cheese for snacks.

When you start this diet, your body will go through an adaptation period which can last from several days to a few weeks and it happens because your body switches to producing energy through fat, instead of carbohydrates. So it is possible that in the first days you will have symptoms such as exhaustion, lethargy, and headaches. These will disappear once the body has adapted. 

Another similar diet to the keto diet is the low-carb diet, the major difference being that in the keto diet there is an even higher restriction of carbohydrates. 

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Health benefits

The main benefits of the ketogenic diet are:

1. Managing seizures and epilepsy

The ketogenic diet generates the production of ketone bodies, such as acetoacetate, acetone and beta-hydroxybutyrate. These substances can reach the brain and exert an anticonvulsant effect.

Therefore, this diet improves how your brain uses energy, and can increase the production of some important neurotransmitters such as GABA. It can also decrease neuronal excitability and improve communication between neurons.

The ketogenic diet is considered to be a safe and effective alternative for the treatment of refractory epilepsy and can help to significantly reduce the number of seizures in adults and children. It should always be recommended under the guidance of a neurologist. 

2. Helping with cancer treatment

The ketogenic diet can help treat cancer, as it has been shown to be effective in reducing tumor size and cancer-related weight loss. This may be due to the fact that it blocks tumor growth by reducing its access to glucose.

For this reason, the ketogenic diet can be used as a complement to cancer treatment, under the guidance of an oncologist.

3. Promoting weight loss

The ketogenic diet helps to keep you full because lipids and proteins generally take longer to digest, and remain in the stomach for a longer time.

In addition, it reduces appetite due to the beta-hydroxybutyrate and acetone produce from this diet. This can also lead to weight loss.

4. Preventing and treating diabetes

The ketogenic diet can also help prevent and treat type 2 diabetes. It helps to keep blood sugars within normal limits, promotes insulin sensitivity and improves hemoglobin-A levels in the blood.

5. Preventing cardiovascular diseases

The ketogenic diet can help prevent cardiovascular diseases, such as atherosclerosis or heart attacks because it is based in a reduced intake of high carb foods and increasing protein intake. This can lead to lower triglyceride levels and better HDL cholesterol in the blood, which is conducive to heart health.

6. Managing blood pressure

The ketogenic diet, especially when maintained for prolonged periods, can help lower blood pressure in people with hypertension.

This is because low-carb, high-protein diets correct abnormalities in glucose and insulin metabolism, reducing blood pressure.

7. Helping to treat neurodegenerative diseases

The ketogenic diet can also help in the treatment of neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, due to the increased production of ketone bodies that improve how the brain uses energy. Its increased antioxidant capacity also protects the brain from toxic substances, such as meperidine-derived MPP free radicals.

8. Helping to treat PCOS

Some studies have shown that the ketogenic diet can help treat polycystic ovarian syndrome (PCOS), as it significantly improves weight and helps balance hormone and glucose levels.

PCOS is a frequent metabolic problem in women, characterized by insulin resistance, abdominal obesity and increased fat in the blood.

What to eat

The foods allowed in the ketogenic diet include:

  • Lean meats and proteins, such as turkey, chicken, lean cuts of beef and pork, and eggs;
  • Fish and shellfish, especially oily fish such as salmon, sardines and trout, squid and prawns;
  • Low-carb vegetables, such as spinach, lettuce, broccoli, onions, watercress, cucumbers, zucchinis, cauliflower, tomatoes, asparagus, red chicory, Brussels sprouts, pak choi, bell peppers, bamboo shoots or alfalfa sprouts;
  • Low-carb fruits, such as blueberries, strawberries, raspberries, cherries, coconut, avocado;
  • Sausages, such as pork ham or natural turkey;
  • Oils and fats, preferably healthy ones, such as olive oil, sunflower oil, grape oil, coconut oil and avocado oil, or butter or cream;
  • Nuts, such as peanuts, walnuts, hazelnuts, Brazil nuts, almonds, peanut butter, almond butter or cashew butter;
  • Seeds and oilseeds, such as linseed, chia, sesame, sunflower or olives;
  • Dairy products, such as plain and unsweetened yogurt, sour cream, cottage cheese, cream cheese, brie, parmesan, feta, cheddar, Swiss, mozzarella and blue cheese;
  • Seasonings, such as pepper, oregano, curry or parsley.

In addition, natural coconut, almond or hazelnut drinks without sugar can also be added.

People with a history of high blood pressure or high cholesterol should reduce their intake of fattier goods, like butter, creams and sausages.

What to avoid

Foods banned from the ketogenic diet are:

  • Cereals, such as corn, oats, cornstarch, wheat flour, bread, toast, cookies, rice or pasta;
  • Legumes, such as beans, chickpeas, lentils or soybeans;
  • Tubers, such as potatoes, sweet potatoes or cassava;
  • Foods prepared with sugar, such as cakes, filled cookies, chocolate, sweets, ice cream, pies, puddings or milkshakes;
  • Simple sugars, such as white sugar, brown sugar or honey;
  • Alcoholic drinks such as beer, wine, gin, rum or cider.

Fruit in general (other than those mentioned above, like berries) are also not recommended in this diet, as most of them are very high in carbohydrates.

In addition, it is advisable to avoid consuming diet foods with sweeteners, as these can affect the acetone levels produced by this diet. They can also be highly processed.

Whenever processed food is consumed, it is very important to look at the nutritional information to check whether it contains carbohydrates and how much, so that you do not exceed the amount that has been calculated for each day.

3-day meal plan

The following table contains an example of a three-day keto diet meal plan:


Day 1

Day 2

Day 3


Eggs fried in butter  +  mozzarella cheese

Omelette made with 2 eggs and vegetable filling  + 1 cup of strawberry juice with 1 teaspoon of flaxseeds 

Smoothie made with avocado, almond milk and ½ tablespoon of chia seeds

Morning snack

Almonds + 3 slices of avocado

Strawberry smoothie with coconut milk + 5 walnuts

10 raspberries + 1 tablespoon of peanut butter 



Salmon with asparagus  + avocado + olive oil

Vegetable salad with lettuce, onion and chicken  + 5 cashew nuts + olive-oil + Parmesan cheese

Meatballs with courgette noodles and Parmesan cheese 

Afternoon snack

10 cashew nuts 2 tablespoons coconut chips  + 10 strawberries

Eggs fried in butter + rennet cheese

Scrambled eggs with oregano and grated Parmesan

It's important to note that the ketogenic diet should be carried out under the guidance of a registered dietitian, who can calculate the grams of carbohydrates that should be consumed per day. A dietitian can also help identify which foods are best for you to consume to achieve your goals. Because this can be a restrictive diet, it is important for a dietitian to help ensure you are getting adequate nutrients in your daily diet.

What is a cyclical keto diet?

A cyclical ketogenic diet helps to maintain diet follow-through and good weight loss, as well as providing energy for physical exercise. 

In this type of keto diet, you follow the keto diet meal plan for five consecutive days, and then you have two days when you can eat carbohydrates, such as bread, rice, and pasta. However, desserts, ice-creams, cakes, and other sugar-rich products should continue being off-limits.

Who should not be on this diet

The ketogenic diet is not advised for those over 65, children and teenagers, and pregnant and breastfeeding women. It should also be avoided by those who have an increased risk of ketoacidosis, such as type 1 diabetics, uncontrolled type 2 diabetics, people with low weight, or with a history of liver or kidneys diseases and cardiovascular alterations, such as a stroke. It is also not recommended for those with kidney stones or anyone taking medications that contain cortisone.

In these cases, the ketogenic diet will need to be approved by a doctor and followed-up by a dietitian.