A common misconception about the ketogenic diet is that it’s all butter and bacon. But the ketogenic diet is actually defined by macronutrient intake rather than food quality, so it’s possible to follow the diet in a healthy or unhealthy way. When patients make poor food choices on a ketogenic diet, they put themselves at risk of nutrient deficiencies, malnutrition, and other health concerns.
Here are the healthy foods that Sheila Dean, DSc, RDN, LDN, IFMCP, suggests be included in the ketogenic diet—as well as a sample menu plan and her recommended supplements.
THE KETOGENIC DIET DEFINED
The ketogenic diet is a high-fat and low-carbohydrate diet. The goal of the diet is to force the body to burn fat as an alternative energy source. When ketone bodies are produced, the body shifts into a metabolic state of nutritional ketosis. The carbohydrate content of the ketogenic diet ranges from 10 to 60 grams per day, but most often is fewer than 20 grams. This number refers to a net intake of carbohydrates, but grams of fiber don’t count. Because of individual variations in biochemistry, not everyone needs to restrict the same amount of carbohydrates to maintain a state of ketosis.
HEALTHY FOODS TO INCLUDE IN A KETOGENIC DIET
Non-starchy vegetables. Many vegetables are low in carbohydrates and provide one of the rare sources of fiber in the ketogenic diet. They also provide important vitamins and phytonutrients. Vegetables like cauliflower, zucchini, and spaghetti squash can substitute for high carbohydrate foods like potatoes, rice and pasta.
Meat and poultry. Organic chicken, turkey, beef, and pork provide a high-quality source of protein and fats.
Avocados. These fruits are high in fiber, vitamins, minerals, and fats, making them a nutrient-dense staple of the ketogenic diet.
Seafood. Salmon, mackerel, and other fatty fish are excellent sources of omega-3 fatty acids. Most seafood contains no carbohydrates, (although some shellfish have small amounts) and are an excellent choice for protein.
Organic Eggs. While egg whites provide a complete protein, egg yolks are the richest source of choline in a typical diet.
Nuts and seeds. These ketogenic diet staples provide essential fatty acids, zinc, selenium, and other minerals. They can also be used creatively in recipes, such as chia seed pudding.
Organic Greek yogurt, cheese, butter, and cream. Pasture-raised, full-fat dairy products with no added sugars are good choices for those who aren’t sensitive to dairy.
Coconut oil. This oil is high in medium-chain triglycerides (MCT), which promote beta oxidation and ketosis.
Olive oil and olives. The stars of the Mediterranean diet are also important in the ketogenic diet as sources of healthy fats.
Coffee and tea. These beverages are carbohydrate-free as long as you don’t add any sweetener. Heavy cream can be added to coffee. A popular morning beverage for many people on the ketogenic diet is “butter coffee”, which is coffee blended with grass-fed butter and MCT oil into a creamy, latte-like beverage.
Optimizing Patient Health During Carbohydrate Restriction
As the ketogenic diet surges in popularity, a wave of dietary supplement products has followed in its wake claiming to enhance benefits of ketosis or minimize the potential risks of the ketogenic diet and ensure adequate nutrient intakes. In a practice paper on the use of the ketogenic diet in epilepsy, the Academy of Nutrition and Dietetics included a summary of supplements to accompany the diet. Here, we explore the rationale and science behind some of these supplement ingredients, as well as the controversial use of exogenous ketone salts.
SUPPLEMENTS FOR A KETOGENIC DIET
The ketogenic diet contains no grains or starchy vegetables. It allows for no fruits except small amounts of low-carbohydrate berries. So even when choosing the healthiest foods for a ketogenic diet, there’s a risk that patients might under-consume some micronutrients, particularly the following: » Fiber » Folate » Calcium » Iodine » Iron » Magnesium » Potassium » Vitamin A » Vitamin B1 (thiamine) » Vitamin C » Vitamin D
To ensure adequate intake of all essential micronutrients, consider supplementing the ketogenic diet with a robust multivitamin and mineral, as well as other supplement ingredients depending on the individual’s dietary pattern and unique biochemistry.
ELECTROLYTES AND TRACE MINERALS
Ketones are osmotically active and can result in increased production of urine. Patients following a ketogenic diet will lose electrolytes in the urine, especially as the body initially adjusts to the diet. Dehydration and electrolyte imbalances might contribute to dry mouth, headaches, or other unwanted effects commonly referred to as the “keto-flu.”
Patients on a ketogenic diet can also lose minerals in the urine. And the diet’s restriction of grains, beans, and root vegetables could contribute to lower intakes of some minerals, such as magnesium, iron, and selenium. That’s why a multivitamin with minerals is the first way to reduce the risk of nutrient deficiencies during a ketogenic diet. Sea salt or iodized table salt can also provide electrolytes and trace minerals.
Some electrolyte supplements are purposely formulated to accompany the ketogenic diet to help maintain electrolyte balance, especially at the beginning stages of the diet, until the body adjusts. These products typically include at least sodium, chloride, magnesium, and potassium and ideally other trace minerals as well.
FIBER, PROBIOTICS, AND DIGESTIVE ENZYMES
The ketogenic diet eliminates all grains and is inherently low in fiber. Because fiber serves as a fuel for the microbes of the intestinal tract, the ketogenic diet leads to changes in the gut microbiome. Supplementing the diet with a fiber powder is a reasonable way to support the microbiome and healthy bowel function.
In a review article published in 2019 in the journal Genes, European researchers summarized nine studies that documented how the ketogenic diet changes the composition of the gut microbiome. The authors concluded by recommending strategies to support gut health during a ketogenic diet, which included supplementation with prebiotics or probiotics.
Also, most people are not accustomed to eating the large amount of fat that constitutes a ketogenic diet. When starting the diet, the high-fat content might make them feel heavy, bloated, or gassy. Plus, the ketogenic diet places an increased burden on the gallbladder to release bile, and on the pancreas to produce lipase enzymes. Some patients might benefit from taking digestive enzymes to help support their bodies in adjusting to a high-fat diet. Particularly useful are products that contain lipases, ox bile or herbs that support bile flow, such as dandelion root or artichoke leaf.
MEDIUM-CHAIN TRIGLYCERIDE (MCT) OIL
Among the types of fats recommended in the ketogenic diet are medium-chain triglycerides (MCTs). MCTs may enhance nutritional ketosis because they so readily oxidize to produce ketones. MCTs can be consumed in foods like coconut oil or supplemented in the form of MCT oil.
Some products combine MCT oil with short-chain fatty acids such as butyrate for a synergistic effect. Butyrate is normally produced by gut bacteria, and has a direct effect on gut health, being an essential energy source for colonocytes and supporting the intestinal barrier.
ACETYL L-CARNITINE
Carnitine is required for the transport of long-chain fatty acids across the mitochondrial membrane for oxidation. The fat content of the ketogenic diet creates a high demand for carnitine. Without an adequate supply, it can become difficult to metabolize fats and maintain ketosis. But despite a reasonable mechanism that suggests an increased need for carnitine during a ketogenic diet, it appears the diet doesn’t typically lead to low levels of carnitine.
A study conducted at Rush-Presbyterian-St. Luke’s Medical Center in Chicago monitored carnitine levels in children who followed the ketogenic diet for two years. Results showed that mild carnitine depletion might occur in the early phases of the diet, but typically normalizes or increases back to baseline with long-term adherence to the diet. Supplementation with an exogenous source of carnitine may not be necessary for all patients on the ketogenic diet, but it’s reasonable to consider for anyone who experiences a change in their ability to maintain ketosis.
KETONE SALTS (EXOGENOUS KETONES)
We end this article with a discussion on one of the more controversial supplement ingredients marketed to patients who are following a ketogenic diet: exogenous ketones. Exogenous ketone supplements usually contain beta-hydroxybutyrate, which is bound as a salt to sodium, potassium, calcium, or magnesium.
Beta-hydroxybutyrate, known as beta-hydroxybutyric acid or BHB, is one of three ketones produced naturally in the body. BHB makes up about 80% of the total circulating ketones in our blood. Acetoacetate and acetone make up the remaining 20% and ~1%, respectively. We know from studies on nutritional ketosis, that ketones cross the blood-brain barrier and can be used as fuel by the brain, especially when glucose is in short supply. They have been shown to be neuroprotective, promoting oxidative defense, and enhancing mitochondrial respiration. In addition to acting as an energy source for the brain, ketones also enhance cerebral blood flow and depress appetite.
But here are the important questions: are these same benefits achieved from supplementing a regular diet with exogenous ketones? And, is there any additional benefit of supplementation when nutritional ketosis is already achieved and ongoing? Proponents for raising blood BHB through exogenous supplementation cite benefits of supporting cognitive and athletic performance and other health benefits, especially for those not adhering to a ketogenic diet, and thereby not endogenously producing any significant number of ketones.
Studies have shown that exogenous ketones may offer metabolic benefits, even in the absence of a carbohydrate-restricted diet. In five separate studies of 39 endurance athletes, researchers at the University of Oxford showed that supplementation with exogenous ketones supported endurance by providing an alternative fuel source, decreasing the breakdown of muscle glycogen, and decreasing the production of lactic acid.
However, some studies of ketone salts have found no benefit compared with a placebo. In one study, 10 people who didn’t normally exercise were supplemented with either beta-hydroxybutyrate or a placebo. The researchers found that the exogenous ketone salts didn’t affect exercise performance or perceived exertion when study participants were walking on a treadmill.
While there may be some benefit to taking ketone salts for those not following a carbohydrate restricted keto-diet, the jury is still out as to whether ketone salt supplementation offers additional benefits beyond following the ketogenic diet alone. In addition, for those following a ketogenic diet, exogenous ketone salts might possibly interfere with some of the health benefits of nutritional ketosis.
The purpose of the ketogenic diet for weight loss is to produce ketones from stored fat as an alternative fuel source. But if your ketone blood levels become too high, your blood can become dangerously acidic. To prevent this, healthy people have a feedback mechanism that slows down production of ketones if they become excessively high.
In other words, the higher your blood ketone levels are, the less your body produces. As a result, taking ketone supplements may prevent body fat from being used as fuel, at least in the short term. Rather than saying these supplements are “ketogenic,” it’s more accurate to say they might mimic the state of nutritional ketosis. This might be a good thing, or it might not, depending on your reasons for being “in ketosis”. Clearly, additional research and clinical studies will be helpful and necessary to answer many of the outstanding questions.