Are Apples Keto? What they don't tell you about Apples on Keto

Apples are a delicious fruit that we have been taught the saying “An apple a day keeps the doctor away”. This saying seems to have been coined in 1913 and originated from the original saying in Wales, "Eat an apple on going to bed and you'll keep the doctor from earning his bread".

Fruits such as apples have become a contentious topic due to the long held belief of its health properties while experiencing a 180 degree turn in the low carb community. In this article, we will explain the strengths and weaknesses of apples with regards to health, nutrition and your personal goals so you can make a strong informed decision on whether is is suitable to include in your personal diet.

According to the USDA, a single medium apple is approximately 169 grams and is 86% water by weight. This serving of apple contains 96.3 kcal of calories.

Apples are a good source of carbs. A single medium apple contains approximately 19 grams of net carbs. The total carbohydrates is 23 grams with 4.06 grams of fiber and 17 grams of sugar. 10.3 grams of sugar is fructose.

Regarding effect on blood sugars, apples have a glycemic index (GI) from 28 to 44 which is low to medium. The highest GI is glucose which is 100.

Looking at the landscape of current epidemiological studies show that eating apples is associated with reduced risk of some forms of cancer (r, r, r), cardiovascular disease (r), asthma (r) and type 2 diabetes (r).

High amount of fructose apples may be problematic for some people

Apples contain a high amount of fructose, consisting of over half of the sugar content. In epidemiological studies, fructose is associated with the risk of cardiovascular disease, type 2 diabetes and obesity. Excessive consumption of fructose can increase the production of uric acid which is a driver of gout, increase the permeability of the gut, cause high blood pressure, increase liver inflammation and cause accumulation of fat in the liver and stomach area (visceral fat) (r, r, r).

For healthy people, fructose shouldn’t pose a problem. In a study of healthy individuals, ingestion of a high dose of fructose for 8 weeks didn’t show any adverse results. However, in the study, patients with non-alcoholic fatty liver disease had increased fat accumulation in the liver and stomach area (r).

People with health problems mentioned above should track their fructose intake. According to a study in 2018, in theory, eating a fructose load under 5 grams may help since it is fully metabolized in the small intestines and doesn’t reach the liver (r, r).

Pesticides are found the pulp of the apple

Apples after harvest usually take some time before they show up in retail supermarket due to supply chain logistics. In order to keep them from browning, apples go through drench treatment in a pesticide called diphenylamine (DPA) and is toxic at high doses and can affect the production of red blood cells. Also DPA has been shown to penetrate the skin into the pulp of the apple and so washing or removing the peel of the apple will not fully prevent ingestion. (r, r)

Eating apple may damage your teeth

According to a study published in the Journal of Dentistry, the higher acidity and sugar content found in apples and other fruits may damage tooth enamel (r, r). So it is recommended to rinse your mouth after eating acidic foods to minimize damage.

Don’t eat the apple seeds

Apple seeds which are generally discarded contain cyanogenic glycosides which are poisonous. Although our body is able to deal with a small amount of cyanide, at a certain dose it becomes toxic. According to Healthline, eating around it takes around 200 apple seeds or 40 cores to ingest the fatal dose.

The focus of the ketogenic diet is the intake of human essential protein, fats, vitamins and minerals. All of which are generally lacking in apples. Apples are high in carbohydrates, mainly in the form of sugar with a high amount of fructose.

Eating a single medium apple will use most of the quota of carbohydrates you can eat in a day to stay under the 25 grams per day of net carbs while not providing much protein and fats that are more important when eating a ketogenic diet. This leaves little to no room for carbs you will eat other foods.

See below on how to eat apples and other carbohydrates while on the ketogenic diet.

Apples are not a significant source of fat and protein. A medium apple contains only 0.2 grams of fat and 0.4 grams of protein.

Apples contain low amounts of vitamins and minerals. The most notable nutrients apple contains are Vitamin C and potassium. However, Vitamin C and glucose compete for uptake in the human body with glucose having higher priority. Since apples are high in glucose, you may not be able to absorb the Vitamin C contained in apples.

Pectin Prebiotic Fiber

Pectin acts as a prebiotic fiber in human nutrition and it is mainly found in plants which function as a structural component of plant cell walls. Although we cannot digest it, it will end up being fermented by our gut bacteria to produce butyrate, a short chain fatty acid which has anti-inflammatory properties. It is the primary fuel used by our intestinal cells helping with the production of mucus to protect the intestinal wall.

Antioxidants in Apple

Apples contain many polyphenols which are considered to be providing the benefits from apples. Laboratory in vitro (cell culture) studies show that compounds such as beta-carotene, quercetin and chlorogenic acid found in apples acts as strong antioxidants and may help bolster the antioxidant system in the body.

Beta-carotene acts mainly as an antioxidant in our body able to neutralize 2 types of free radicals in our body. We also have a small capacity to convert 0-8% this compound into Vitamin A. Note that some people are not able to do this. (r)

Quercetin found exclusively in the peel of the apple also acts as an antioxidant and is found to inhibit various kinds of tumor growth in breast, colon and intestines. Low levels of quercetin was also found to inhibit platelet aggregation and mobilize calcium which may help in cardiovascular disease. (r)

Apples contain chlorogenic acid which is also found in coffee and decaf coffee, has mild stimulatory effects and cognitive benefits similar to caffeine and acts as an antioxidant in the body. (r)

The procyanidins, epicatechin and catechin found in apple also acts as antioxidants and is found to protect LDL from oxidation. This is protective against cardiovascular disease as it is thought that oxidized LDL is what accumulates in arteries causing blockages (r).

When trying to lose weight on a ketogenic diet, it is generally recommended that you avoid apples as they are very high in sugar. This would cause your body to produce a high amount of insulin and in turn slow down fat loss in your body. If you must eat apples trying to lose weight, here are a few tips that can help counter the effects.

1. Eat a very small amount. As the saying “The dose makes the poison”, a third of an apple would probably be okay to eat as a treat. Pay attention to other foods you are eating as well that are high in carbohydrates.
2. Try eating it at night. After a long day of using your body, it generally becomes more insulin sensitive and your fat loss probably won’t be affected by a small amount of apple.
3. Do a few body weight exercises like squats or take the dog around the block for a walk. Working your body will use up some of the sugar (glycogen) stored in your muscles, so the carbohydrates you eat will be used to replenish those muscles instead of storing them in your fat cells allowing you to continue burning your fat stores.

Unfortunately, other than some sugar, apples don’t provide much benefit to workouts and athletic activities. While working your body on a ketogenic diet, you will want to focus on protein, fats and minerals, ideally from meat which will provide your body with the resources to build muscle and energy to move. On a ketogenic diet, your body becomes metabolically flexible, able to use both carbohydrates and fats effectively to provide energy for movements. Eating too many carbohydrates may in turn cause your body to focus on using carbohydrate, rather than using both.

Since the sugar in apples mostly consists of fructose, the sugar will provide your muscles with less energy than you think it may. Fructose is not metabolised by muscles cells and mostly only processed in the small intestines and liver to replenish its glycogen stores.

Apples can be part of a healthy diet and can even work on a ketogenic diet.

Although the general rule told all keto dieters are to stay under 25 grams of net carbs a day to stay in ketosis or just to continue burning fat, how many net carbs one can eat is specific to each individual and is affected by many factors such as physical activity, total calories and even the types of fat you eat.

Going in and out of ketosis is a natural physiological response depending on what you are eating and that’s okay!

Implementing the following can help you return to ketosis more quickly:

1. Choose a smaller apple, fit it into 25g carb daily limit.
2. Eat it after doing some resistance exercises.
3. Take 2 tablespoons of apple cider vinegar before eating it to reduce insulin release. (r)