List of Foods to Eat and Avoid for Ketogenic Diets

It is not widely known that ketogenic ('keto') style diets have existed since the 1920s. The high-fat and low-carbohydrate diet showed promise in helping reduce seizures in pediatric patients with epilepsy. Today the keto diet is promoted for weight loss. Many people were introduced to the “keto” or “ketogenic” diet via the Aitkin diet methods. The low-carb diet phenomenon, began in the 1970s with the Atkins diet (a high-protein diet, very low-carbohydrate diet which was a popular and quite successful). This diet introduced many people to the use of keto sticks to measure ketone levels in the urine.

Today, many other low-carbohydrate diets are popular including the Dukan, Paleo, and South Beach Diets. All of these diets are high in protein, but low to moderate in fat. In contrast, the keto or ketogenic diet stands out for its every high-fat content, typically 60% to 80% fat, combined with relatively moderate levels of protein in most versions. However, there are many variants of the ketogenic diet and foods allowed and disallowed. This article aims to clarify which foods are 'in-and-out' for keto diets.

There are a wide range of foods permitted on the Keto Diet.
There are a wide range of foods permitted on the Keto Diet. Source: Unsplash free images; Public Domain

How The Keto Diet Works

The principle for using the ketogenic diet for weight loss is that if you deprive the body of glucose by restricting carbohydrates in the diet the body switches to an alternative fuel called ketones, produced from stored fat. Hence, this is the derivation of the term “keto”-genic. When fasting, starving or doing extreme exercise, or when very little carbohydrates is consumed, the body initially draws on glucose reserves such as glycogen stored in the liver. The body also temporarily breaks down muscle and muscle glycogen to release glucose. After about 3-5 days of carbohydrate depletion, the glucose reserves are fully depleted. The levels of insulin in the blood decrease dramatically, and in response to this hormone, the body switches to using fat as its primary source of fuel for its energy needs. The liver starts producing more and more ketone bodies from fat, which the body uses to fuel its metabolism in the absence of glucose.

The accumulation of ketone bodies in the blood is called 'ketosis'. Healthy people experience a mild and natural ketosis during periods of fasting (including overnight fasting while sleeping) and after very strenuous exercise. Proponents of the ketogenic diet contend that if the diet is carefully followed, the levels of ketones in the blood should not reach dangerous level (known as “ketoacidosis”). This occurs in individuals with type 1 diabetes because they do not produce insulin. There is little evidence of ketoacidosis being cause by a normal ketogenic diet.

It should be noted that can get the benefits of ketosis and weight loss while eating a varied and balanced Mediterranean-Diet by undertaking intermittent fasting and reducing food consumption. One example is to 'not eat lunch' and to focus on eating whole foods. This method includes intermittent fasting and calorie intake reduction by about 30%.

Grilled fish and low carbohydrate leafy greens and vegetables are a good keto diet choices
Grilled fish and low carbohydrate leafy greens and vegetables are a good keto diet choices. Source: Unsplash free images; Public Domain

Tips for Getting into Ketosis

There are a several ways you can use to get into nutritional ketosis safely and effectively.

The keo diet includes moderate to high levels of protein, and high fat
The keo diet includes moderate to high levels of protein, and high fat. Source: Unsplash free images; Public Domain

How Long Does it Take to Shift to Ketosis

It generally stakes 3-5 days for your body to enter ketosis and 1-3 weeks for your body to adapt to using ketones for fuel.

Measuring Your Ketosis State Using a Urine Test

Keto urine test strips are a cheap and convenient way of finding out if you’re in ketosis. They were originally developed for people with type 1 diabetes to check for the onset of diabetic ketoacidosis, a potentially life-threatening condition cause by extremely high levels. Urine Keto test strips are readily available over-the-counter at your local pharmacy. They’re relatively inexpensive and are easy to use. The strips typically expire within 3-6 months after opening. It is best to do your test at the same time each day, such as in the morning or several hours after your last meal of the day, for a reliable comparison to check your progress.

Avocado and many green low starch vegetables are allowed on the keto diet
Avocado and many green low starch vegetables are allowed on the keto diet. Source: Unsplash free images; Public Domain

Guide to the Ketogenic Diet

There is no classic 'one-size-fits-all' ketogenic diet with a 'locked-in' ratio of macronutrients (carbohydrates, fat and protein). Most ketogenic diets that people adopt typically includes:

For a typical 2500-calorie diet, this is equivalent to a daily intake of about 40 grams carbohydrate, 165 grams fat and 75 grams protein.

In comparison, the general Dietary Guidelines for Americans recommends that people get :

Note that the amount of protein for the ketogenic diet is moderate rather than high, compared with other low-carbohydrate & high-protein diets (such as Aikens and Paleo), because eating too much protein, which breaks down to glucose can prevent ketosis.

Many versions of ketogenic diets exist, but all focus on banning carbohydrate-rich foods. This includes the obvious ones such as starches from both whole grain and refined baked foods such as breads, cereals, pasta, rice, cakes, pies and cookies. It also includes starchy vegetables such as potatoes, corn, turnips and most root vegetables, It also includes most fruits and fruit juices that have high natural sugar contents. Beans, nuts, dried fruits and most legumes, are also excluded due to their high calorie levels.

Salads with tuna and eggs can be eaten on the ketogenic diet
Salads with tuna and eggs can be eaten on the ketogenic diet. Source: Unsplash free images; Public Domain

Typical Allowed Food Choice Strategies on the Keto Diet

Typical Foods Excluded on the Keto Diet

List of Specific Allowed Foods on Ketogenic Diets

List of Specific Foods to Avoid on Ketogenic Diets