The Pros and Cons of the Keto Diet

Learn about the pros and cons of the Keto Diet - a low-carb, high-fat diet for weight loss and blood sugar control. What are the benefits and drawbacks?
Medical Reviewer: Julia Axelbaum, RD
Published on: April 21, 2023
Updated on: March 5, 2024

Learn more about how FORM pairs patients with a doctor and dietitian to achieve their weight loss goals.

Keto Diet Notebook and Foods


Although it may seem trendy, the ketogenic or ‘keto’ diet has been around for over 100 years. With roots as a therapy for reducing seizures in pediatric patients with epilepsy, the keto diet is a high fat, low carbohydrate approach that’s meant to stabilize blood sugar levels. While there is no standard macronutrient breakdown, the keto diet is approximately 70% fat, 15 to 20% protein and 5 to 10% carbohydrate – or less than 50 grams of carbohydrates a day.

The premise of the keto diet is that by restricting carbohydrates your metabolism will transition from using glucose, the body’s main energy source, to using dietary fat and fat that is stored in fat tissue, also called adipose tissue. This fat is then broken down into ketone bodies, for energy. When your body has fewer carbohydrates it goes into a ‘ketogenic’ mode because your liver produces ketone bodies when fat is metabolized for energy.

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Metabolic outcomes such as weight loss may vary based on the level of carbohydrate restriction, protein intake and quality of fat (animal vs. plant sources). The popularity of keto-type diets such as the Atkins diet, Zone diet, South Beach Diet, and Paleo diet, which promote a fat-burning state of ketosis for weight loss, has fluctuated over the years. Recently, nutrition science has supported the keto diet for treating neurodegenerative diseases, such as Alzheimer’s disease, autism spectrum disorder, as well as metabolic diseases, such as type 2 diabetes and obesity. 

Let’s look at some of the pros and cons of the keto diet.

Pros of the Keto Diet

One pro of the keto diet is its effect on appetite and metabolism. In some studies, the keto diet has been shown to decrease appetite and increase lipolysis, the breakdown of fats. This results in fat metabolism being more efficient as the rate of calories burned, called the thermic effect, increases slightly. The keto diet has also been shown to suppress hunger when you are consuming fewer calories. In addition, the keto lifestyle strictly limits processed foods that can lead to weight gain and other disease states. 

Eliminating Sugary Foods and Beverages

Another pro of the keto diet is that you eliminate sugar sweetened foods and beverages, which can help with weight loss and maintenance, as well as decrease the risk for type 2 diabetes, heart disease and certain cancers. It’s important to be thoughtful about using sugar replacements such as artificial sweeteners to cut back on sugar which may have negative effects on your gut health. Research has revealed that regularly consuming artificial sweeteners may disrupt the structure and function of the gut microbiome.  Not all sugar substitutes are created equally, however. Extracts from the stevia plant, a non-nutritive sweetener, has been shown to lower insulin and glucose levels, and lead to feelings of fullness regardless of its low calorie level. More research is needed on how stevia affects the bacteria in the gut. 

How Keto Affects Inflammation in the Body

One controversial topic about the keto diet is how it affects inflammation in your body. On one hand, the keto diet has been shown to have anti-inflammatory effects in the body as it aids in fat loss and lowers circulating insulin in the body. Since adipose tissue (fat tissue) and high insulin levels are pro-inflammatory, it makes sense that a diet that reduces body fat and increases insulin sensitivity will, in turn, decrease inflammation, which may also help with cardiovascular health. The results from several large studies examining dietary patterns and their effects on cardiovascular outcomes, show improved cardiovascular risk factors from a low carbohydrate and high fat diet compared to a low fat diet with at least 50 percent of carbohydrate of total calories.

On the other hand, studies have shown that a high-fat meal can increase inflammation and trigger pro-inflammatory activation of immune cells in people with insulin resistance or Type 2 diabetes. One of the solutions supported by research is post-meal exercise. Taking a walk after a high-fat meal has been shown to help counteract the inflammatory response and improve blood sugar control. Why is this? Exercise helps muscles better utilize glucose for energy and increase insulin sensitivity, which can decrease inflammation in the body. Keep in mind, more research is needed to assess if the benefits decrease over time and what the long-term effects of the keto diet are on cardiovascular health. 

Cons of the Keto Diet

One con of the keto diet is that avoiding fiber-rich whole grains and starchy vegetables can lead to decreased microbial diversity in the gut, which can affect immune health. Plus, it can be difficult to eat a diet that is so low in carbohydrates over the long-term. Additionally, highly processed foods full of fillers and artificial sweeteners, especially sugar alcohols (i.e., xylitol, maltitol, and sorbitol), which are devoid of nutrients, can become quick go-to’s for people trying to stick to a keto diet on the go.

Starvation Ketosis

Low-carb intake requires daily discipline to stay in nutritional ketosis; if done improperly it can lead to a condition called ‘starvation ketosis’, in which extremely low carbohydrate and protein intake causes an overabundance of ketones that can lead to muscle loss and life-threatening deficiencies in electrolytes and essential vitamins and minerals. In addition, deviating from this strict eating plan may not only lead to weight gain, but can have negative psychological consequences such as shame and guilt, which may lead to disordered eating behaviors.

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Potential Side Effects

Other cons of the keto diet are its potential side effects. While it may take anywhere from 3 to 10 days to achieve ketosis, the beginning phases of low carbohydrate consumption may cause bad breath, headaches, nausea, fatigue, flu-like symptoms, and constipation. Long-term consequences can include gastroesophageal reflux disease (GERD), high levels of uric acid – a metabolic waste product of high protein foods, electrolyte imbalance and hyperlipidemia.

The bottom line is that there are both pros and cons of the keto diet and it requires supervision and support along the way. The scientific consensus is that more evidence is needed to confirm its effectiveness and safety. If you want to try a keto diet, the best bet is to work with a team that includes registered dietitians and physicians who specialize in this approach to get personalized macronutrient goals to ensure that you are helping – and not harming your health. 

How FORM Can Help You with a Keto Diet

At FORM, the clinical team can help you with a modified ketogenic diet, which includes high quality carbohydrates, such as whole vegetables, fruits, whole grains, beans, peas and lentils, to get a daily dose of beneficial fiber, as well as vitamins, minerals and plant compounds that can support your weight loss efforts and overall health. Each FORM patient works with a registered dietitian and weight loss doctor to develop a personalized plan to help them meet their health goals. 

Visit FORM online for more information or schedule a call to get your questions answered. Ready to get started? Take our quiz to see if FORM is right for you.

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