From the perspective of nutrition physiology, eating food serves the purpose of supplying the body with nutrients and water.
During a ketogenic diet, it is necessary to ensure a certain macro-nutrient composition (see chapter
Basics Ketogenic Diet)
to archieve and maintain the metabolic state of ketosis. The so-called "macros" can be checked with the help of
nutritional labelling on food packaging and nutrition tables.
More or less independent of the kind of diet, additional nutrient requirements must be met.
To maintain all its functions, it is important to get all micronutrients the human body needs.
The body also synthesizes many substances it needs by itself. However, there are some cases when this doesn't work and sufficient
amounts have to be supplemented from external sources. These substances are called essential nutrients. In adult human beings,
these essential nutrients consist of eight amino acids, two fatty acids, some minerals and trace elements, and all the vitamins,
whereby vitamin D is the exception because, apart from its dietary uptake, it can be produced in the skin if exposure
to solar radiation is sufficiently provided. There are recommendations for the quantitative supply of most essential
nutrients, for example, those published by the Food and Nutrition Board of the Institute of Medicine which apply for the USA and
Canada. The table below shows a list of essential nutrients and indicates exemplary foodstuffs which might serve as adequate sources
for a ketogenic diet.
| Name | Important Sources |
|---|---|
| FAT-SOLUBLE VITAMINS |
|
| Vitamin A | Carrots (contain the plant-based provitamin form), egg yolk, liver, cod liver oil, butter |
| Vitamin D | Egg yolk, certain types of fish, cod liver oil |
| Vitamin E | Sunflower oil, canola oil, olive oil, linseed oil, hazelnuts, Brazil nuts, walnuts |
| Vitamin K | Most vegetables, although in varying quantities, canola oil, egg yolk |
| WATER-SOLUBLE VITAMINS |
|
| Vitamin B1 | Pork |
| Vitamin B2 | Chicken eggs |
| Vitamin B6 | Different types off fish, certain types of meat, walnuts, hazelnuts |
| Vitamin B12 | Most types of fish, egg yolk, beef, pork |
| Biotin | Egg yolk, walnuts, hazelnuts |
| Vitamin C | Most vegetables |
| Folic acids | Vegetables, hazelnuts, Brazil nuts, walnuts, egg yolk |
| Niacin (or vitamin B3) | Fish, meat, peanuts |
| Pantothenic acid (or vitamin B5) | Vegetables, fish, meat, egg yolk |
| MINERALS | |
| Calcium | Calcium-rich mineral water, certain vegetables, Brazil nuts, hazelnuts |
| Chlorine | Table salt |
| Potassium | Nuts, peanuts, vegetables, fish and meat, hen's egg yolk and egg white, hen's egg white protein powder |
| Magnesium | Hazelnuts, walnuts, Brazil nuts, peanuts, magnesium-rich mineral water |
| Sodium | Table salt |
| Phosphor | Nuts, meat, fish, egg yolk |
| Sulfur | protein-containing foods |
| TRACE ELEMENTS | |
| Cobalt | Found in Vitamin B12 |
| Iron | Red meat, poultry, certain types of fish |
| Iodine | Iodized table salt, most sea fish |
| Copper | Nuts, certain meats, fish and vegetables |
| Manganese | Nuts, certain vegetables |
| Selenium | Fish, egg yolk and egg white, certain fish, nuts |
| Zinc | Meat, fish, egg yolk, nuts |
| ESSENTIAL AMINO ACIDS |
|
| Isoleucine | Meat, fish, eggs, protein powder |
| Leucine | |
| Lysine | |
| Methionine | |
| Phenylalanine | |
| Threonine | |
| Tryptophan | |
| Valine | |
| ESSENTIAL FATTY ACIDS |
|
| Linoleic acid | Sunflower oil, canola oil, linseed oil, olive oil, Brazil nuts, walnuts, hazelnuts |
| alpha-linolenic acid | Linseed oil, canola oil, walnuts |
Fatty acids are coarsely distinguished in monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and saturated fatty acids (SFAs). The former should make up the main proportion in this form of diet, they primarily originate from animal food products or from canola and olive oil. You take up most of the SFAs by eating animal food products. The percentage of these substances should not be too high. To the group of the PUFAs belong the two essential fatty acids alpha-linolenic acid (omega-3-fatty acid) and linoleic acid (omega-6-fatty acid). While the fulfillment of the demand for these acids must be secured, the quantitative ratio of the two fatty acids is also important (omega-6-fatty acids / omega-3-fatty acids = at maximum 5 /1). Both requirements will be easy to meet due to the high fat content of this diet form, and if the foods are well chosen. Apart from fulfilling the body's dietary demands, the supplied quantity of PUFAs should not be too high because they are much more prone to undergo oxidation.
Note: The vitamin E demand increases the more PUFAs you consume. As PUFAs in this type of diet are taken up predominately in the form of unprocessed vegetable oils and nuts, the somewhat increased demand for this vitamin (compared to most other diets) will be automatically met.
After several weeks and some routine with this diet you will be able to estimate quite well how often you eat the respective foods. Then you should compare the essential nutrients of your personal diet with the nutrient supply reference values reported in nutritional value tables. You will find the age and sex-dependent supply recommendations for the respective nutrients, for example, on the DRV Finder on the EFSA website. First open the DRV Finder:
You can also look up the nutrient contents of most foods online.
In case of a (distinctly) too low supply of single nutrients, you will have to adjust your personal food selection. For an initial orientation, you can use the data shown in the table above. If necessary, you might have to supplement one nutrient or another. You will be able to purchase suitable products at a low price in pharmacies and drug stores. Always make sure that the dose of single vitamins, minerals or trace elements never (markedly) exceeds your requirement. Always mind the nutrition facts and the dose information printed on the package and seek advice from your pharmacist or doctor whenever you are not sure.