Why Keto and Carnivore Diets Aren’t Sustainable | OnPoint Nutrition

SORRY! YES, WE SAID IT.

With promises of rapid weight loss, improved energy, and even better mental clarity, Keto and Carnivore diets have captivated millions. And yes, while these diets can sometimes yield quick results, the long-term sustainability and health implications are worth examining closely.At OnPoint Nutrition, we are at the frontlines of all the fads and all of the fails. We have seen it all and we have seen thousands who have muddled their way through countless quick fixes and restrictive diets that maybe started off strong, but ultimately lead to more frustrations – for one reason or another.

This blog will dive into why Keto and Carnivore diets might not be the best choice for lasting health, providing insight into their impact on the body, the risks of extreme restriction, and alternative approaches that support balanced, sustainable wellness.

Understanding the Keto and Carnivore Diets: What Are They?

The Ketogenic diet is a high-fat, low-carbohydrate eating plan that shifts the body into ketosis, a state where it burns fat for fuel instead of glucose. By drastically reducing carbs, the body is forced to use ketones (byproducts of fat breakdown) as an energy source. Many people follow Keto for weight loss or to stabilize blood sugar, but it requires strict adherence to low-carb intake—often under 50 grams per day—to maintain ketosis.

The Carnivore diet, on the other hand, is a form of extreme elimination diet that consists solely of animal products—meat, fish, eggs, and sometimes dairy. Proponents of Carnivore claim benefits like reduced inflammation and weight loss, but the diet entirely excludes plant foods, which eliminates fiber, key vitamins, and antioxidants.

The Nutritional Imbalance and Deficiencies of Keto and Carnivore

One of the biggest downsides of Keto and Carnivore diets is their restrictive nature, which limits the intake of various essential nutrients that come primarily from fruits, vegetables, whole grains, and legumes. Research suggests that dietary diversity plays a major role in supplying the body with vitamins, minerals, and fiber, which are crucial for functions like digestion, immune health, and cellular repair.

The Risks of Fiber Deficiency

Fiber, which is almost entirely absent in Carnivore and low in many Keto diets, is essential for healthy digestion. Fiber helps regulate blood sugar, supports beneficial gut bacteria, and aids in satiety, reducing cravings for high-calorie foods. The average American consumes about 16 grams of fiber daily—already below the recommended amount. Both Keto and Carnivore diets can further decrease fiber intake, leading to digestive issues and a higher risk of diseases like colon cancer and cardiovascular disease.

Lack of Antioxidants and Phytonutrients

Fruits, vegetables, and whole grains provide essential antioxidants and phytonutrients that combat inflammation and oxidative stress. Keto limits many antioxidant-rich foods, while Carnivore excludes them entirely, potentially compromising the body’s ability to neutralize free radicals and protect against chronic illnesses.

High Saturated Fat Intake and Cholesterol

One significant concern with Keto and Carnivore diets is the high intake of saturated fat, especially when animal products like fatty cuts of meat, cheese, and butter become staples. While the research on saturated fat is nuanced, multiple studies indicate that diets high in saturated fats may increase LDL (bad) cholesterol, which can lead to an elevated risk of heart disease.

Lack of Heart-Healthy Nutrients

Diets rich in plant-based foods, like fruits, vegetables, and whole grains, provide nutrients that support cardiovascular health, such as potassium, fiber, and unsaturated fats. In contrast, animal-based diets often lack these heart-protective nutrients, potentially leading to imbalances that could increase blood pressure, inflammation, and cholesterol levels.

Ketosis and the Potential Strain on the Kidneys and Liver

Achieving ketosis—especially in the extreme conditions of the Carnivore diet—places added stress on the kidneys and liver. These organs work to process the byproducts of protein and fat metabolism, which can lead to dehydration and an increased burden on the kidneys. Long-term ketosis can raise the risk of kidney stones, a particular concern for those predisposed to kidney conditions.

Excess Protein and Nitrogen Waste

Carnivore diets, in particular, are high in protein, which produces nitrogen waste that the kidneys must filter out. Research shows that high-protein diets can stress kidney function over time, particularly in individuals with underlying kidney issues. Without the balancing effects of hydration and fiber from fruits and vegetables, the risk of kidney stones may rise.

The Mental and Emotional Toll of Restrictive Eating

While Keto and Carnivore diets can yield initial weight loss, their extreme restrictions can be mentally challenging. Constantly monitoring carb intake (in Keto) or limiting every meal to animal products (in Carnivore) can lead to diet burnout, making it harder to maintain these eating patterns over time. Studies on restrictive diets have shown that they may increase feelings of deprivation and lead to eventual overeating or “yo-yo dieting,” which is linked to negative mental health outcomes.

Impact on Social and Family Life

Restrictive diets can also limit social interactions around food, making it difficult to enjoy meals with friends and family or partake in cultural food traditions. This can create a sense of isolation or guilt, which can affect long-term adherence and contribute to a cycle of starting and stopping these diets without lasting success.

Alternatives for Sustainable Health and Weight Management

If Keto and Carnivore diets aren’t ideal for long-term health, what’s the alternative? Nutritionists and dietitians typically recommend balanced, whole-food-based diets that include a variety of nutrient-dense foods. These approaches focus on quality, flexibility, and gradual change rather than extreme restriction, making them more sustainable and enjoyable over time.

The Mediterranean Diet: A Balanced, Evidence-Based Option

The Mediterranean diet, rich in fruits, vegetables, whole grains, healthy fats, and moderate protein, is consistently linked to reduced risks of chronic diseases, including heart disease, diabetes, and certain cancers. Unlike Keto and Carnivore, the Mediterranean diet encourages a balanced approach that can be adapted to individual preferences and lifestyles.

Flexibility with the 80/20 Approach

Another sustainable approach is the 80/20 rule, where 80% of your food choices focus on nutrient-dense, whole foods, and the remaining 20% allows for flexibility. This framework supports long-term adherence by incorporating treats and indulgences in moderation, removing the feeling of deprivation. And think about it — 20% sounds like decent amount of room for some fun foods that you love. Hello, peanut butter cookies!

How a Dietitian or Nutritionist Can Help You Find the Right Approach

If you’re seeking sustainable health improvements or weight management, a nutritionist or dietitian can provide a personalized approach that considers your unique needs, preferences, and goals. They can help you set realistic goals, find balance, and make gradual adjustments that fit into your daily routine.

Real-Life Results and Lasting Change

Working with a professional means receiving evidence-based advice tailored to you, rather than following a one-size-fits-all plan. Research confirms that customized nutrition counseling is more effective for maintaining long-term health changes compared to self-guided diets.

Building Lasting Health

While diets like Keto and Carnivore may seem appealing due to their quick results, the long-term reality often falls short. The restrictions, nutrient deficiencies, and potential health risks make these diets challenging to sustain, especially without professional guidance. Instead, choosing a balanced, flexible approach allows you to enjoy food, feel satisfied, and achieve sustainable health.

Partnering with a dietitian or nutritionist can provide the knowledge, support, and motivation you need to reach your goals in a way that lasts.

Ready to take the first step?

Our team at OnPoint Nutrition is here to help you build a balanced, sustainable approach that honors your health and fits seamlessly into your life.