Keto diet: forbidden foods

The keto (=ketogenic) diet is based on a drastic reduction of carbs, which can range from 50 grams[1] [2] [3]up to zero (carnivorous diet). Managing your carbohydrate intake is therefore essential to be able to reach the state of ketosis. One can also have a low-carb diet, which can be up to 130 carbs per day.

Keto diet: foods to avoid

To properly follow a ketogenic diet, there are certain foods to avoid given their carbohydrate content. These include (the carb count is always per 100 grams of product):

Starchy foods

Foods such as beans (41 grams of carbohydrate, excluding green beans, which have only 7), peas (61 grams per 100 grams on average, excluding peas, which have about 9 to 10 grams), lentils (20 grams per 100 grams).

However, alternatives exist such as low-carb pasta and derivatives like risoni.

Cereals and their derivatives

The rice(around 77 grams), corn (19 grams), wheat (28 grams of carbohydrates), barley (73 grams), millet (63 grams), oats (66 grams), seigle (61 grams) and derivatives such as pasta (this can vary from 30 to 70 grams per 100 grams of product depending on the type of pasta chosen, how it is cooked and whether it is a prepared dish), cereal bars or breakfast cereals, bread (about 49 grams, it varies depending on the type of flour used), bagels (same amount as bread), tortilla style patties(20 grams in one patty)and baked goods in general (a muffin, for example, has 46 grams of carbohydrates).

Keto alternatives exist for tortillas, the bread and the doughnuts

Vegetables with a high carbohydrate content

Vegetables that contain more digestible carbohydrates than fibre should be limited in a ketogenic diet. These include potatoes(15 grams), sweet potatoes (17 grams), panais (13 grams), and the squash family (about 14 grams, except spaghetti squash, at 7 grams). Other vegetables, such as onion, carrots, celeriac (all at 7 grams of carbohydrates) should be eaten in moderation so as not to exceed the daily macros.

Fruit

Also limit fruits high in sugar. Foods such as bananas (20 grams), grapes (16 grams), mango (13 grams), pineapple, kiwi, apples, pears (12 grams each) or oranges, cherries, watermelon and mandarines (10 grams), abrics (9 grams) increase blood sugar easily. Other fruits to avoid or eat in moderation are melon and plums (7 grams), as well as dates (75 grams) and dried fruits such as prunes (64 grams), and any candied fruit.

Sweetened drinks and alcohol

Any type of sweetened drink, such as sodas (a can of Coca-Cola, for example, contains 37 grams of carbohydrates), fruit juice with or without sugar (depending on the brand it varies, but it can range from 10 grams per 100 ml for a sugar-free orange juice to 20 or 25 grams if there is added sugar), sugared lemonades, sirops, are a highly concentrated source of carbs and easily raise blood sugar. Consider that a standard size glass contains 200/220 ml. Consumption of sugar-free sodas is also not recommended, as artificial sweeteners also raise blood sugar[4] and their health impact is highly controversial.

With regard to alcohol, all cocktails containing sugar or made with fruit puree should be avoided, as well as beer(between 8 and 22 grams in general depending on the brand), sweet wines and preparations that mix spirits and sweetened sodas.

There are now beers andwines that are sugar free.

Sugar in all its forms

All forms of sugar are not suitable for a ketogenic diet: white, red, coco, fructose, dextrose, sucrose, glucose, honey, isoglucose, maltose, inverted sugar, dextrin, maltodextrin, syrup of any type (maple or agave, among others), as well as sugar such as candy, cakes, sweetened yoghurt, sugary desserts, confections, etc. Basically, avoid anything that contains any form of sugar, either simple or complex, natural or artificial. Preparations with sweeteners other than stevia, erythritol or xylitol are not advised for the same reasons mentioned above regarding sodas.

Find the healthy sweeteners compatible with a keto diet here. 

Sweeteners

When buying sauces or prepared foods, pay attention to the carbohydrate content, as many of them are filled with sugar. For example, a ketchup has an average of 26 grams of carbs per 100 grams, BBBQ sauces, 40 grams, non-household vinaigrettes can quickly go up to 20 grams. Watch out for soy sauces that are not gluten free, as they can also have a high carb count.

Find here alternatives for sugar-free sauces

Vegetable oils

Finally, processed vegetable oils should be avoided, as they are extremely inflammatory[5] [6]and alter the microbiota[7]: margarine, hydrogenated oils, partially hydrogenated oils and other trans fats, sunflower oil, safflower, cotton, canola, soybean, grape seed and corn are all harmful to health. Trans fatty acids and processed oils are oxidised during high temperature processing, creating free radicals. Natural trans fats, such as those found in dairy products and in the meat of grazing animals are not harmful to health.

Find the recommended vegetable oils for a healthy, ketogenic diet here.

In two words

To properly follow a ketogenic dietyou need to limit your carbohydrate intake to between 0 and 50 grams of carbohydrates per day. Industrial products, such as chips, crackers, nachos, sauces, desserts, breads and the like, should therefore be eliminated. Some foods that may be keto compatible, such as cashews (7.7 grams), for example, should be consumed in moderation. The key to keto success is to plan aheadand also to read labels well to avoid hidden carbohydrates in foods such as hams, deli meats or condiments.

[1] https://www.ncbi.nlm.nih.gov/books/NBK537084/

[2] https://academic.oup.com/ajcn/article/86/2/276/4633078

[3] https://onlinelibrary.wiley.com/doi/full/10.1111/obr.12230

[4] https://www.nature.com/articles/nature13793

[5] https://pubmed.ncbi.nlm.nih.gov/17224066/

[6] https://pubmed.ncbi.nlm.nih.gov/16841858/

[7] https://pubmed.ncbi.nlm.nih.gov/22570770/