The keto diet is a high-fat diet that restricts carbohydrates to 20-50 grams per day to achieve a metabolic state called ketosis. Ketosis is the state of the body when glucose is unavailable to expend energy, while the body burns fat and produces ketones. 

Choosing the right kind of beverages to drink is important to remain in ketosis. This is very difficult to do considering most sodas and alcoholic drinks contain plenty of sugar. For instance, a can of Pepsi contains 41 grams of carbs, easily crossing the prescribed limit of carbs, thereby ruining your dietary goals.   

Eight ounces of cranberry juice contains roughly 30 grams of carbs, having the same effect. These drinks can easily knock you out of ketosis and stop the diet’s success in its tracks for people who drink sodas in huge quantities. However, certain alcoholic drinks such as red and white wine, if consumed in small amounts, can still help maintain ketosis. 

Coke Zero Versus Regular Coke

Diet coke has a distinctive taste different from the popular soft drink under the same brand, Coca-Cola Classic. A regular can of 360 ml contains 39 grams of carbohydrates, making it easy to exceed the limit of carbohydrates allowed on the keto diet.  

In 2005, Coca-Cola Zero Sugar was introduced in the market as a novel soft drink with zero calories, until it was rebranded and renamed in 2017. The change was intended to make the taste of Coke Zero similar to the classic one, without sugar content. 

GettyImages-634597354 Pallets of Coca-Cola Zero Sugar (Coke Zero) cans wait to the filled at a Coco-Cola bottling plant on February 10, 2017 in Salt Lake City, Utah. by George Frey/Getty Images

Is Coke Zero Healthy?

Coke Zero offers no calories as artificial sweeteners, such as acesulfame potassium and aspartame, are added for taste. Consuming the drink will not disturb your state of ketosis, but both sugar substitutes have negative consequences on health, particularly causing metabolic syndrome. Therefore, exercise precaution if you choose to drink Coke Zero amidst the list of keto foods. 

When digested, aspartame is broken down into three main chemical compounds, namely aspartic acid, methanol, and phenylalanine. All three chemicals are toxic to the body when moderation is not exercised. Methanol turns into free methanol in raised temperatures, eventually transforming to formaldehyde, a carcinogen as classified by the Environmental Protection Agency (EPA). As per the American Cancer Society, exposure to formaldehyde can cause myeloid leukemia. 

The other chemical, phenylalanine, is considered safe to be added to whole foods according to the Food and Drugs Administration (FDA). It is a concern for people with the genetic disorder phenylketonuria (PKU) as it can lead to brain damage, behavioral problems, mental disorders and seizures. 

Caffeine is also bad for health. A can of Coke Zero ( 355 ml) is filled with about 34 mg of caffeine for every 12 ounces. Caffeine might seem to boost energy levels, but in the long-run caffeine could lead to anxiety and sleeping problems. Also, if an individual drinks 15 cans of Coke Zero continuously, it could result in dehydration caused by excessive urination.

Depression, anxiety, Alzheimer's disease, diabetes, fibromyalgia, epilepsy and parkinson’s disease are some of the other major side effects of consuming aspartame.  Hence, it is safe to say that you should be wary of Coke Zero while following the keto diet.