While there are many cure-all claims found on the internet these days many of them lack research or validation. The keto diet, however, is the exception that proves the rule: there is compelling scientific evidence that supports the efficacy of the ketogenic diet for a number of health conditions.
Click to jump to a specific section:
Medical nutrition therapy is the term used to define when dietary changes are used therapeutically to treat or improve diseases, conditions, and symptoms. Hundreds of published studies show a ketogenic diet to be beneficial for a variety of health conditions including obesity, diabetes, metabolic and brain diseases, seizures and more. Recent research is also exploring the possibilities for using the keto diet as a component in cancer therapy. The ketogenic diet, therefore, is a type of medical nutrition therapy.
A ketogenic diet is a powerful way to manage many diseases, and research proves it as seen above! Less studied benefits and claims not yet substantiated include prevention and remission of all cancers, long-term improvements in digestive function, and improved management of schizophrenia and bipolar disorder.
What is the Keto Diet?
As a quick review, the ketogenic diet is a low-carbohydrate, high-fat diet. When done correctly, the foods you eat contain high-quality, healthy fats like avocado, coconut oil, and extra virgin olive oil. Meats, dairy, eggs, and animal fats ideally come from grass-fed or pasture-raised aminals to avoid consuming too many agricultural toxins or pesticides. It's also important to remember that meat coming from conventially ranched animals is much higher in pro-inflammatory omega 6 fatty acids, due to their high soy and corn diets.
The keto diet also requires the consumption of lots of leafy greens and other low-carbohydrate fruits and vegetables. Low-carb vegetables include crucifers like kale, broccoli, cauliflower, and Brussels sprouts, in addition to other leafy greens like spinach, arugula, leaf lettuces, and chard. While fruits do contain some natural sugars, what matters most about your carb consumption on the keto diet are net carbs.
Review the previous section for more details on the key terms you need to know when considering the keto diet.
1. Keto Helps Fight Obesity & Promote Weight Loss
The most common American use for the keto diet is weight loss. Most Americans follow the standard American diet (SAD for short). The main hallmarks of this way of eating are that it's
- too high in processed carbohydrates and meats
- too high in sodium
- too low in nutrient-dense foods like colorful fruits and vegetables.
The incorrect assumptions of the 1980s and 1990s that high-carb, low-fat diets are good and high-fat diets are bad are partially responsible for this trend toward the obesity-causing SAD diet. The rise in convenience foods (including packaged snacks) and overall decline in home-cooking are also major contributors. This way of eating has resulted in epidemic levels of obesity in the US. The ketogenic diet offers a solution that doesn't feel like a deprivation diet, due mostly to its high-fat requirements.
Why Does Keto Work?
The short answer is nutritional ketosis. Ketosis is the state that occurs when your body begins burning ketone bodies instead of carbohydrates for energy. The goal of the keto diet is to reduce carbohydrate consumption enough to force your body into a state of ketosis. Once this takes place, fat replaces glucose as your body's main source of energy, and you become a fat-burning machine.
When your body is burning fat instead of carbohydrates, AND you're eating at a calorie deficit, you will begin burning your own body fat at a rate faster than your average low-carb diet like the Atkins diet.
Rapid weight loss on this diet (including up to a 10-pound drop in the first week, due to a loss of water weight) will help you stick with it. It's also a lot easier to stick to for the long term than fad diets because it doesn't leave you feeling hungry all the time. By reducing your carb and sugar intake and replacing it with fat, you'll eliminate extreme spikes and drops in your blood sugar levels, which will keep hunger at bay.
The keto diet isn't just a short-term weight loss solution. As long as you maintain ketosis at a calorie deficit, you will continue to lose weight in the longer term. Multiple studies show that continued body fat loss, even at the 24-month mark remains possible because the body converts fat to ketones for fuel in the absence of enough carbohydrates.
Another reason for sustained weight loss on this diet is likely because it doesn't reduce your resting metabolic rate. Most extremely low-calorie weight loss plans send your body into starvation mode and dramatically reduce your metabolic rate. This is likely to sabotage your long-term success. One study showed that obese patients on a very low-calorie version of the keto-diet maintained their resting metabolic rate while on the plan, likely due to the fact that they were able to maintain lean body mass while losing body fat. Add resistance training to your routine for added benefits.
Once you've reached your goal weight, you can up your calories while remaining in ketosis in order to maintain your weight and continue reaping the health benefits of the keto diet.
2. Keto Helps Prevent and Reverse Type 2 Diabetes
Most of what we've outlined above is applicable to type 2 diabetes prevention and reversion. While it's possible to look thin on the outside while struggling with your blood sugar levels, most type 2 diabetes patients also struggle with their weight. And chances are, if you're thin with diabetes, you're "TOFI" (thin on the outside, fat inside) – meaning you have more visceral fat hiding under your muscles than you think (and it's likely contributing to your disease).
Visceral fat (fat that collects in your midsection and in your organs) is a hallmark of metabolic syndrome. Metabolic syndrome can lead to type 2 diabetes and cardiovascular disease. It's more dangerous than subcutaneous fat (visible fat that sits atop muscle and feels soft to the touch) because of the effect it has on your body systems. One study showed that a low-carb diet was more effective at reducing visceral body fat than a low-fat diet.
We've already mentioned the positive effects that the keto diet has on blood sugar control. When compared to low-glycemic diet, the keto diet is more effective, at least in the case of this study of online participants. That's likely because the very low-carb nature of this diet reduces the need for the body to create insulin.
Type 2 diabetes is not actually the result of an insulin deficit; it's due to insulin resistance, which takes place because of an abundance of insulin, which damages the walls of blood cells. In other words, a reduction in insulin production (due to the low-carb nature of the keto diet plan) gives your blood cells a chance to regain some insulin sensitivity. The increase in insulin sensitivity will actually help prevent or even reverse diabetes (or metabolic syndrome) over time.
An important note: ketosis is not the same thing as ketoacidosis. Ketoacidosis is a risk factor in uncontrolled diabetes patients (both types). It happens when there's an unhealthy build-up of ketones and your insulin levels are critically low. The result is extreme dehydration (sometimes to the point of being fatal), so it's important to have a doctor monitoring you if you have diabetes. A standard ketogenic diet or low-carb diet should not trigger ketoacidosis.
3. Keto Contributes to a Healthy Heart
Again, the evidence we've already outlined above applies to this section as well. A reduction in the risks for type 2 diabetes and metabolic syndrome is also a reduction in the risk of heart disease or other cardiovascular diseases like stroke. But that's not the only reason the keto diet supports a healthy cardiovascular system.
In addition to providing major benefits to blood sugar levels and a reduction of visceral body fat, the keto diet has also been shown to dramatically reduce triglyceride levels in the blood and increase the size of LDL cholesterol particles.
For a quick review of cholesterol, we know that having high levels of small, very dense LDL cholesterol particles in the blood is associated with a greater risk of heart disease. The larger your LDL particle size, the less sticky it is and the less potential there is for it to create blockages in your arteries and increase blood pressure.
We also know that a high ratio of HDL to LDL is beneficial for heart health. While there's still more work to be done in this area, preliminary studies indicate that a ketogenic diet can help improve that ratio.
Contrary to conventional advice from dietitians, reducing your dietary cholesterol doesn't actually have much effect on your cardiovascular risk. That's because dietary cholesterol and saturated fats (the kind that comes in delicious, keto-friendly foods like eggs, coconut oil, and animal fats) doesn't actually raise your blood cholesterol levels in a way that's detrimental to your cardiovascular health.
In fact, tons of research shows that high-fat diets (especially monounsaturated fats like the kind you find in olive oil and avocados) actually raise HDL levels. And dietary carbohydrates do just the opposite, especially highly processed, high-glycemic ones. It's the processed carbs that impact the HDL to LDL ratio and negatively affect LDL particle size.
It would then follow that a low-carbohydrate diet would necessarily be beneficial for overall heart health, as long as it's rich in nutrient-dense foods.
4. Keto Has Been Shown to Treat Epilepsy
One of the original uses of the keto diet dating all the way back to the 1920s is for the treatment of drug-resistance epilepsy, especially in children. More recent studies have shown greater than a 50% reduction in seizure occurrence for children on a ketogenic diet. That's a major change! The explanation for these effects is due in part to a disruption of signaling in the hippocampus and liver. A study on rats supports this theory, in addition to the many studies on epileptic humans.
Side effects reported after kids were on the diet for three months included constipation, vomiting, hunger, and lethargy.
5. Keto Shows Promise with Neurodegenerative Conditions
In the case of Alzheimer's, the keto diet's effectiveness is, in part, due to the protection of hippocampal neurons by ketones. Hippocampal neurons are largely responsible for memory and learning and are vulnerable to degeneration in Alzheimer’s.
In the case of ALS, much more work needs to be done. The findings are somewhat inconsistent, but the overall evidence shows that dietary fats can have a protective quality for mitochondrial function, and ALS is a mitochondrial disorder. In other words, if dietary fats can help improve mitochondrial function (the part of your cells that helps you create energy), and ALS is the result of mitochondrial dysfunction and degeneration, it would follow that a high-fat diet could help ALS patients. The research hasn't totally borne this out just yet, but the preliminary findings seem promising.
While more research needs to be done, a promising study comparing the effects of a low-fat diet and a keto diet on 47 Parkinson’s patients showed significant improvements in nonmotor symptoms in the keto group over the low-fat group. This is an especially exciting finding because nonmotor symptoms are less responsive to the widely used Parkinson’s drug, levodopa. Nonmotor symptoms include urinary problems, pain, fatigue, daytime sleepiness and cognitive impairment. Both groups showed improvements in motor symptoms.
6. Keto Gives Hope to Cancer Patients
Cancer cells feed on glucose, just has healthy human cells do. However, research has uncovered a critical detail that could bring the keto diet into the standard treatment plan for many cancer patients: cancer cells can’t burn ketones for fuel the way healthy human cells can. They need the glucose and can’t reproduce without it.
A study done on mice with metastatic cancer demonstrated that the keto diet decreased tumor viability and actually prolonged the lives of the mice. Scientists believe that one factor in why this is happening is the mitochondrial dysfunction in tumor cells. The dysfunction inhibits the cells from using ketones as energy and prevents them from growing or reproducing. And because the healthy cells surrounding the tumor are ketone-adapted, they create an unfavorable environment for the cancer cells. This leads researches to hypothesize that the ketone bodies themselves might have anti-cancer properties.
Ketone supplementation was part of this study, and more work needs to be done before these methods become the standard recommendation, but this research is exciting news for cancer patients looking for strategies to bolster the efficacy of their current treatment plan.
The Keto Diet Benefits Your Health
The ketogenic diet is a powerful way to manage many diseases, including obesity, type 2 diabetes, cardiovascular disease, epilepsy, and neurodegenerative diseases. While there’s more work to be done, research supports keto’s efficacy in a number of important areas of human health. Further areas of study that haven't yet been rigorously investigated include the keto diet's effect on the prevention and remission of all cancers, long-term improvements in digestive function, and improved management of schizophrenia and bipolar disorder.
For now, it’s well-established that the keto diet is an excellent tool for weight loss, blood sugar control, mid-section fat loss, and the treatment of epilepsy. To learn about some of the risks of the keto diet, continue to our next article.
Written by: Natalie Butler, RDN, LD & Toni Sicola.
Published: July 12, 2019
Updated: August 7, 2019
Jump to Another Section of the Beginner's Guide to the Keto Diet
1. What is Keto? | 2. Keto Health Benefits | 3. Keto Health Risks | 4. Keto Nutritional Macro Calculations | 5. Foods to Eat on Keto | 6. Foods to Avoid on Keto | 7. Keto Supplements | 8. Free Keto Meal Plan | 9. Get Started on Keto | 10. Keto Recipe Book