Four Potential Downsides of the Ketogenic Diet

Photo: ifong/Shutterstock.com

Four Potential Downsides of the Ketogenic Diet

The ketogenic diet has been very popular for several years now with plenty of cookbooks, programs, products, and practitioner certifications available to support both providers and the general public. The defining principle of the ketogenic diet is that it severely restricts the intake of carbohydrates to less than 50 grams per day. For comparison, the average person consumes 265 grams per day. It also relies on consuming a very high percentage of fat per day, often at levels of 70-80 percent of the total daily caloric intake. When carbohydrates are kept low enough, the body will use fat rather than glucose as its fuel source.

Known for its use in the treatment of epilepsy, the ketogenic diet has also been studied for its potential benefits for cancer, obesity and diabetes, Alzheimer’s disease, and even for attenuating inflammation in some individuals with COVID-19.

Although there may be undeniable promise and benefits to this diet for certain health conditions, there are also potential downsides to consider. Each person is unique, and people can address these potential limitations by working with a qualified health (functional medicine) practitioner who can help them navigate this therapeutic dietary pattern.

Here are four areas for greater awareness:

Increased Exposure to Lipophilic Toxins

Unlike other low-carb diets, the ketogenic diet emphasizes the high consumption of fat. Many environmental toxins are lipophilic, which means they get stored in adipose tissue and can accumulate with ongoing exposure. Examples include:

When you consume food sources of fat contaminated with these toxins, you become exposed and increase your toxin load. In various populations, these toxins have been linked to an increased risk of developing various diseases, including stroke, cognitive disorders, blood sugar dysregulation, obesity, autoimmune disorders, and reproductive disorders.

To reduce toxic fats, choose foods with relatively lower toxin levels, such as organic cuts of meat, organic produce, and wild fish. Note that choosing organic foods unfortunately doesn’t completely protect you from contaminants, but it’s a relatively better choice.

Risk of Metabolic Endotoxemia

Studies have shown a link between diets higher in fat and an increased risk of metabolic endotoxemia. Metabolic endotoxemia occurs with high amounts of lipopolysaccharides (LPS, also known as endotoxin) in the blood due to an excess of gram-negative bacteria in the gut. This increase of circulating endotoxin leads to low-grade systemic inflammation and associated chronic illnesses.

A mouse study found that while a high-fat diet induced metabolic endotoxemia, supplementation with phlorizin, a phytochemical found in apples, was able to modulate the gut microbiota and attenuate the deleterious effects of the dietary pattern. The high-fat diet caused a significant increase in serum LPS levels while also impacting microbial abundance. While phlorizin was able to significantly inhibit the increase in LPS, it did not significantly impact the decrease in short-chain fatty acid production that was seen in the mice consuming a high-fat diet.

Although many of the studies demonstrating the connection between high-fat diets and metabolic endotoxins follow a pattern similar to a Western diet rather than a ketogenic diet, there have been studies demonstrating that high levels of healthy fats, such as coconut oil, may also contribute to metabolic endotoxemia.

The evidence is limited at the moment for a direct connection between a ketogenic diet and metabolic endotoxemia. One mouse study did show the potential ability of the ketogenic diet to reduce acute inflammation upon exposure to endotoxin, but it did not go into details about the impact of chronic consumption of high amounts of fat on the diet. More research needs to be conducted.

Other studies have shown that the ketogenic diet increases some beneficial bacteria, such as Akkermansia muciniphila, while decreasing Bifidobacterium and Lactobacillus. A study comparing the American Heart Association Diet against the modified Mediterranean-ketogenic diet (MMKD) found that the MMKD increased the short-chain fatty acids propionate and butyrate while decreasing acetate and lactate in patients with mild cognitive impairment.

A ketogenic diet generally incorporates less fiber compared to more plant-centric diets, which could also negatively impact the microbiome and lead to dysbiosis. Various studies have found that while dietary fat facilitates endotoxin transport by chylomicrons, fiber delays fat absorption which in turn could positively impact circulating levels of LPS. It is possible to reduce some of the inflammation and other issues through consuming prebiotic fiber, such as inulin.

Dietary Fat Quality and Ratios

Another potential downside of the ketogenic diet is that some people believe it gives them free rein to consume excessive amounts of any type of fat from any food source. Various fats have different impacts on the body, and everyone responds uniquely depending on the broader context of their biochemistry, genes, stress level, and gut microbiome profile. A study comparing the effects of daily consumption of butter, coconut oil, or olive oil found that while coconut oil and butter are both rich sources of saturated fat, they had differing effects on LDL, HDL, and the triglyceride to HDL ratio.

In general, fats such as monounsaturated fatty acids and polyunsaturated fatty acids, especially omega-3 fatty acids, have often been shown to have an inverse association with certain diseases, such as cardiovascular disease and metabolic disorders. Conversely, trans fat and saturated fat have been associated with a higher risk of these diseases, although this area remains the subject of ongoing debate.

My take is that it’s not so much about maligning a particular category of fat, such as whether something is “polyunsaturated” or “saturated.” Rather, it’s largely about the dietary ratios between all these fats within the foods they occur, their relative ratios in our blood and tissues, and what the other nutrient components are in the food source.

Let me restate: no particular source of fat is truly “bad” – it’s about looking at the bigger picture of the food and the meal composition. That said, only focusing on the total quantity of fat for a ketogenic diet without paying attention to the quality of the fat source may potentially lead to health issues like increased inflammation down the line, depending on health risk factors, genes, and environment.

Reduced Intake of Vegetables and Fruits

If you have followed my work for any length of time, you know that the one research point in nutritional science that I can surely stand behind is the importance of colorful food. I am not alone; several other researchers and clinicians cannot argue with the benefits of consuming vegetables and fruit. Numerous studies demonstrate a decreased risk of chronic disease and mortality in those who consume more fruits and vegetables, thanks to their high levels of essential vitamins, minerals, antioxidants, and other phytochemicals. Studies have found that the health benefits rise with the more vegetables and fruits consumed.

However, fruits and vegetables also inherently contain some amount of carbohydrates. When you consume a ketogenic diet that is supposed to have under 50 grams of carbohydrates per day, it becomes very difficult to consume the recommended 9 to 14 servings of fruits and vegetables per day. It is important to take care when creating your meal plans for this type of diet that you include quality fruits and vegetables as much as possible, especially those high in fiber, rich in nutrients, and lower in carbohydrates. As previously discussed, the modified Mediterranean-ketogenic diet is an option that allows for greater plant diversity in the diet.

Closing Thoughts

If you choose to embark on the ketogenic diet, it is best to educate yourself as much as possible to determine the healthiest, best way to make sure it works for you. It is also important to consider why you are wanting to follow this diet in the first place and set goals that motivate you to adhere to the plan.

A study comparing adherence to the ketogenic versus Mediterranean diet found that participants were challenged in following the ketogenic diet long-term because the carbohydrate restriction limited their options. They often had to eat separate meals from their family. Adherence was highest during the first four weeks of the study, during which meals were delivered. Participants requested recipes and meal plans for the eight weeks they would be preparing their own food, but researchers found they did not use these materials and adherence was more variable. Blood ketone measurements, which indicate a state of ketosis, were highest when participants had their food delivered and returned to beginning levels by the end of the 12-week intervention. This study provides useful insights into some of the challenges associated with maintaining this dietary pattern.

If you plan to make dietary changes, have food allergies, or have questions about which eating style is best suited to your personal needs, talk to your doctor, nutritionist, dietician, or another member of your healthcare team for personal options based on your individual circumstances.

 

 

Previous

Next

Submit a Comment

Your email address will not be published. Required fields are marked *

X