Ketogenic Diet Foods

Published: 26 Jan 2023

The ketogenic diet alters the intake of three types of macronutrients—carbohydrate, fat, and protein. You should regulate the amounts of foods you eat containing these macronutrients if your doctor or dietitian recommends that you undertake a ketogenic diet for epilepsy management.

All food packaging in the UK should list the mass in grams of each type of macronutrient in the ‘nutritional information’ section—you can use this information to add up and monitor your daily intakes.

Carbohydrates

With keto, the most substantial nutritional change is in carbohydrate intake, which is decreased to low or very low levels depending on the type of ketogenic diet.

According to the UK government’s Scientific Advisory Committee on Nutrition (SACN), the recommended daily intake of carbohydrates for adults and children aged 15+ should be 333g per day for males and 267g for females. Ordinarily, carbohydrates make up over half (55%) of our daily recommended calorie intake.

In a classical ketogenic diet (CKD), carbohydrate intake is reduced to between 20–50g, equivalent to 5–10% of your total daily calorie intake. This is obviously a significant dietary change, especially for children, which is why it is important that keto is only undertaken under the guidance of a doctor or dietitian.

The amount of dietary carbohydrate reduction varies between different types of ketogenic diet. Your doctor/dietitian should be able to advise you on which type of keto diet is best for you.

Some carbohydrate-containing foods are typically allowed in a ketogenic diet while others are excluded entirely. The following carbohydrate-containing foods are fully excluded from a keto diet:

Bread/baked goods:

•         Crisps
•          Rice
•          Pasta
•          Cereals/grains
•         High-sugar-content foods including confectionery, sugary drinks, and sweet desserts.

These carbohydrate-containing foods are permitted in limited amounts:

•         Dairy products containing lactose.
•         Fruit
•         Vegetables

It’s important to note that some of the permitted carbohydrate-containing foods contain higher levels of carbohydrates than others. One small banana can contain up to 20mg of carbohydrates all by itself, and starchy vegetables like potatoes, corn, peas and legumes are all relatively high-carb.

When thinking of ways to replace sugar in our diet, many people’s minds will go straight to sweeteners as the most obvious replacement. However, not all sweeteners are ketogenic-friendly, as carbohydrates can be present in sweetener ingredients in forms other than sugar.

The Ketogenic Dietitians Research Network has produced a handy resource evaluating different sweeteners and their suitability for a ketogenic diet. You can download their guide here.

Fats

The calorie deficit caused by lowering carbohydrate intake is made up by replacing energy derived from carbohydrates with energy derived from fats.

The recommended daily amount of dietary fat varies dependent on age and sex, but the UK Government recommends that fat intake should not exceed 35% of daily calorie intake in a standard diet. By contrast, ketogenic diets are very high in fat, with fat constituting up to 90% of the dieter’s calorie intake.

Usually, in a well-regulated ketogenic diet, consumption of high levels of fat will not cause the dieter to gain fatty weight. This is because consumed fat is quickly used to replenish the diminishing fat stores in the body, which burn faster during ketosis (the core bodily mechanism which is stimulated by the ketogenic diet).

The effect of increased dietary fat consumption on cholesterol levels is currently under-researched. Some limited studies have found that increased fat intake can lead to higher levels of LDLs in some dieters, while other papers have seen decreases in both HDL and LDL cholesterol in their study population. Further research is required to ascertain the effect of low-carb high-fat diets on cholesterol levels, and whether this effect differs based on body mass, the presence of pre-existing conditions, age, race, or sex.

Very little evidence-based guidance exists regarding the types of fatty foods that can be eaten in high quantities on a ketogenic diet. There is a broader on-going scientific debate about whether saturated fats are less harmful to cardiovascular health than previously thought, but research is still far from conclusive and opinions differ. Many public health organisations still recommend limiting intake of saturated fats and

sticking to unsaturated fats as much as possible instead.

Mono- and poly-unsaturated fats occur naturally in some nuts, seeds, and plant oils, while saturated fats are most commonly found in fatty/processed meat, cheese, and dairy products. The Great Ormond Street Hospital’s website advises that fat intake in a ketogenic diet should rely on foods that are naturally high in fat like double cream, butter, oil and avocado.

Protein

Protein is used in our bodies to maintain, grow, and repair our bodily tissues. When the body is in a state of ketosis, the protein in muscle tissues is at risk of depletion. Protein can be metabolised into energy for the body, replacing the energy usually provided by carbohydrate. Tissue protein levels could deplete if the amount of dietary protein is not maintained, leading to muscle and organ damage.

This means that in a ketogenic diet there must be a moderate intake of protein to maintain our bodies’ tissues.

However, if too much protein is eaten, the body will mine the excess protein for energy by replacing the energy from ketones (desirable on a ketogenic diet) with energy from glucose (derived from protein metabolites). This prevents or disrupts ketosis, defeating the purpose of the diet.

Protein-rich foods include meat, dairy products, and fish. Pulses such as beans, peas and lentils are good alternatives for vegetarians, although they also contain relatively high levels of starch, which will increase your carbohydrate consumption. Visit the NHS Eatwell website for a simple overview of the nutritional properties of different food groups.

Cooking for keto

There’s no need to feel limited in what you eat on a ketogenic diet. There are plenty of great resources out there providing recipes and food advice.

The BBC good Food magazine has this great guide to ketogenic recipes, listing recipes for everything from baked fish and salads to barbecued bavette steak, curries and frittatas. Meanwhile, Keto-Mojo has a large archive of ketogenic recipes and articles listing good and bad food to eat while on keto and the Epilepsy Society has produced this handy guide to diet and nutrition in epilepsy.

If you’re looking for some additional interesting ketogenic-friendly food ideas, check  out this resource on eQOL!