The ketogenic diet (KD), characterized by low carbohydrate and high-fat intake, has gained popularity as a potential therapeutic intervention for various health conditions. Nutritional ketosis, the goal of KD, is achieved by restricting carbohydrate intake, moderating protein consumption, and increasing fat consumption. This dietary approach shifts the body's primary fuel source from glucose to ketone bodies derived from fat metabolism. Recent studies suggest that LCHF diets, such as KD, may aid in weight loss, reverse metabolic syndrome symptoms, reduce or eliminate insulin needs for type 2 diabetics, reduce inflammation, improve epigenetic profiles, alter the microbiome, improve lipid profiles, supplement cancer treatments, and potentially increase longevity and brain function.
Understanding the Ketogenic Diet
The ketogenic diet is a reversal of the current food pyramid supported by the dietary guidelines. Thus, instead of a diet rich in carbohydrates, it is high in fat. The resulting carbohydrate restriction lowers blood glucose levels, and the subsequent insulin changes will instruct the body to change from a state of storing fat to a state of fat oxidation.
Once fats are utilized as the primary fuel source in the liver, the production of ketone bodies begins, a process known as ketogenesis. During ketosis, three major ketone bodies are formed and utilized by the body for energy: acetone, acetoacetate, and β-hydroxybutyrate. All cells that contain mitochondria can meet their energy demands with ketone bodies, including the brain and muscle.
The Ketogenic Food Pyramid: A Visual Guide
A food pyramid is a visual blueprint for how you should eat. The closer a food is to the base of the pyramid, the more servings of that food you’re supposed to consume. The Ketogenic Food Pyramid is commonly referred to as a form of nutritional guide. The food sources are categorized among 3 different tiers on a scale. The number of servings for each amount of food per day differs accordingly.
The keto food pyramid is starkly different from the Food Guide Pyramid. Instead of relegating fats to the top, fats form the base.
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Base: Healthy Fats and Oils (4-10 servings per day)
It may seem counterintuitive, but to burn fat on the Keto diet, most of your calories must come from fat. That’s why healthy fats form the base of the Keto food pyramid. Healthy fats like olive oil, avocado oil, coconut oil, butter, ghee, lard, and tallow form the base of the Keto food pyramid. This doesn’t mean, however, that dinner is a stick of butter. It just means that most of your calories will come from these sources.
This means cooking with coconut oil, dumping olive oil on your salad, making fat bombs, etc. Be creative. Remember you’ll also get some healthy fats from other foods in higher portions of the pyramid, like animal proteins, nuts, seeds, and dairy products.
Second Tier: High-Protein Foods (4 servings per day)
Next up are healthy protein sources like meat, fish, and eggs. Protein is crucial for maintaining muscle, balancing hormones, and supplying the raw materials to build the brain chemicals known as neurotransmitters. Protein is also highly satiating. This is probably why high-protein diets tend to be effective for weight loss. The daily recommendation of intake is 4 servings per day. However, the consumption should be limited to ultra-processed meats such as sausage and hamburgers.
Third Tier: Low-Carb Vegetables and Avocados (2-4 servings per meal)
Your Keto meals should be rich in low-carb vegetables and avocados. These Keto-friendly plants supply loads of micronutrients without kicking you out of ketosis. Here’s a partial list: Avocados, Kale, Spinach, Cauliflower, Broccoli, Asparagus, Lettuce, Bok choy, Cabbage, Green beans.
Keep in mind that starchy vegetables like sweet potatoes, carrots, cassava, and parsnips are largely forbidden on Keto. Too many carbs.
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Fourth Tier: Nuts, Seeds, and Dairy (1-2 servings per day)
You can enjoy almonds, macadamia nuts, hazelnuts, pumpkin seeds, sunflower seeds, and other nuts and seeds as an occasional Keto snack. They’re rich in fiber, protein, and healthy fats. However, If you’re trying to lose weight, be aware that nuts, seeds and nut butters are calorically dense and easy to overeat. Enjoy in moderation. Also, feel free to dabble in dairy products if you can tolerate them. Whey protein, for instance, is high in amino acids like leucine (for muscle growth) and immune-boosting compounds like lactoferrin.
Summit: Keto Fruits and Sweets (One small handful per day)
Atop the Keto pyramid are berries and other semi-low-carb treats. Enjoy these Keto tidbits occasionally and in moderation: Berries like blueberries, raspberries, and blackberries, Dark chocolate (with a minimum of 85% cocoa solids), Citrus fruits, Coconut meat, Tomatoes.
Macronutrient Ratios in the Ketogenic Diet
On a Keto diet, you consume 55 to 75 percent of your calories from fat, 15 to 35 percent from protein, and under 10 percent from carbs. Bear our Keto macros pyramid in mind each time you build your plate. The Keto macros pyramid is a useful tool for structuring meals. It encourages you, for instance, to favor fatty protein sources (salmon, ribeye, chicken thighs, eggs, etc.) because these foods are more ketogenic than leaner options.
Beverages on Keto
If a beverage doesn’t contain carbohydrates, assume it’s Keto-approved. Without calories from carbs or sugar, a drink won’t inhibit fat burning and kick you out of ketosis. This means that beverage selection on Keto is a fairly binary process. It’s either allowed or it isn’t. Keto-friendly beverages include: Water, Coffee, Tea (black, green, white, or herbal), Lemon water, Bone broth, Naturally flavored zero-calorie water or soda.
Alcohol is an edge case. While alcohol itself doesn’t contain carbs, most alcoholic beverages (beer, cocktails, wine) do. And even if you drink zero-carb distilled spirits, your body will still regard alcohol as toxic. More than one or two per day is not recommended.
Read also: The Keto-Brain Fog Link
What about diet sodas? They won’t shut down fat burning, but some evidence suggests that artificial sweeteners like saccharin interfere with gut microbiome health. If you want to play it safe, it’s best to avoid them.
Structuring Keto Meals
To structure your Keto meals, follow these three principles: Ensure you’re hitting your Keto macros (i.e., the Keto macros pyramid), Favor whole food sources of fat and protein, Eat lots of non-starchy vegetables for vitamins, minerals, and menu variety.
Dirty Keto vs. Whole Foods Keto
You’ve probably heard of a dirty Keto diet. It’s a species of Keto that follows the correct macros but ignores food quality. Dirty keto is high in processed meat and vegetable oils-and low in nutrient-dense vegetables. It might help with weight loss, but it’s not geared towards longevity. If you care about your long-term health, it makes sense to adopt a whole foods Keto diet. That’s the operating principle of the Keto food pyramid displayed above. Just eat whole foods, healthy fats, and plenty of low-carb veggies to satiety. Keto sounds simple when you put it that way, doesn’t it?
Potential Health Impacts of the Ketogenic Diet
The potential therapeutic impacts of the ketogenic diet on the microbiome, epigenome, diabetes, weight loss and cardiovascular disease. The KD diet could potentially increase genetic diversity of the microbiome and increase the ratio of Bacteroidetes to Firmicutes. The epigenome might be positively affected by the KD since it creates a signaling molecule known as β-hydroxybutyrate (BHB). KD has helped patients with diabetes reduce their HbA1c and reduce the need for insulin. There is evidence to suggest that a KD can help with weight loss, visceral adiposity, and appetite control. The evidence also suggests that eating a high-fat diet improves lipid profiles by lowering low-density lipoprotein (LDL), increasing high-density lipoprotein (HDL), and lowering triglycerides (TG). Due to the Warburg effect, the KD is used as an adjuvant treatment to starve cancer cells, making them more vulnerable to chemotherapy and radiation.
The Microbiome
The microbiome consists of trillions of microscopic organisms in the human gastrointestinal tract. It comprises over 8000 different types of bacteria, viruses, and fungi living in a complex ecosystem. Recent research suggests that the genetic make-up of a microbiome can be affected by lifestyle factors which include but are not limited to sleep, exercise, antibiotic use, and even diet. A study exploring the benefits of prebiotic foods, such as inulin and oligosaccharides, observed an increase in the number of Bifidobacteria in the colon and the presence of other critical butyrate-producing bacteria.
Currently, scientists do not have any data on the long-term effects of the ketogenic diet on the gut microbiome. Based on various studies, many predict that the diet will positively affect the microbiome by increasing the Bacteroidetes and Bifidobacteria species associated with improved health and decreasing microbial species known to increase health risks. In fact, a study found that the disrupted gut microbiota of epileptic infants was improved with a one-week ketogenic diet, which managed to increase their Bacteroides amount by ~24%. Another 6-month study on children with refractory epilepsy found a significant decrease in Firmicutes and an increase in Bacteroides although the overall diversity decreased. Studies have shown that a low ratio of Firmicutes to Bacteroidetes is an indicator of a healthy microbiome.
The Epigenome
Epigenetics refers specifically to changes “on top” of the genome that can modify and alter levels of gene expression. These epigenetic markers are heritable, yet recent research suggests that some changes can be reversed or occur through environmental changes. Some ketogenic food sources that positively regulate epigenetic activity are cruciferous vegetables, dietary fiber, foods rich in long-chain fatty acids, and berries, such as raspberries. The benefits of some of these food sources have a multitude of positive effects. For instance, black raspberries not only positively affect methylation patterns in the WNT-signaling pathway, but they also profoundly impact the microbiome make-up (increased Lactobacillus, Bacteroidaceae, and anti-inflammatory bacterial species), and increased production of butyrate by fermentation in the gut.
A literature review argued that a state of nutritional ketosis will positively affect mitochondrial function and enhance resistance to oxidative stress and noted that the ketones directly up-regulate bioenergetic proteins that influence antioxidant defenses.
Diabetes
KD has helped patients with diabetes reduce their HbA1c and reduce the need for insulin. The ketogenic diet was commonly used to help control diabetes in the 19th century. Many researchers believe these diseases are a result of carbohydrate intolerance and insulin resistance. Thus, a diet that reduces the exposure to carbohydrates, including whole grains, might become a more logical recommendation for improving health.
Weight Loss
There is evidence to suggest that a KD can help with weight loss, visceral adiposity, and appetite control. The premise of the ketogenic diet for weight loss is that if you deprive the body of glucose-the main source of energy for all cells in the body, which is obtained by eating carbohydrate foods-an alternative fuel called ketones is produced from stored fat (thus, the term “keto”-genic).
Cardiovascular Health
The evidence also suggests that eating a high-fat diet improves lipid profiles by lowering low-density lipoprotein (LDL), increasing high-density lipoprotein (HDL), and lowering triglycerides (TG). All of these negative health markers increase the risk of cardiovascular disease, diabetes, stroke, and Alzheimer’s disease.
Considerations and Potential Risks
While the ketogenic diet has shown promise in various areas, it's essential to consider potential risks and consult with healthcare professionals before adopting this dietary approach.
- Nutrient Deficiencies: Low-carb diets are at greater risk of being nutritionally inadequate by lacking in fiber, necessary vitamins, minerals, and iron. It is important to not solely focus on eating high-fat foods, but to include a daily variety of the allowed meats, fish, vegetables, fruits, nuts, and seeds to ensure adequate intakes of fiber, B vitamins, and minerals (iron, magnesium, zinc)-nutrients typically found in foods like whole grains that are restricted from the diet.
- Long-Term Effects: While the ketogenic diet might be useful to those wanting to manage their weight or diabetes, some argue that there is a lack of longitudinal studies investigating the long-term impact of adopting this type of diet.
- Ketoacidosis: Excessive ketone bodies can produce a dangerously toxic level of acid in the blood, called ketoacidosis. During ketoacidosis, the kidneys begin to excrete ketone bodies along with body water in the urine, causing some fluid-related weight loss. Ketoacidosis most often occurs in individuals with type 1 diabetes because they do not produce insulin, a hormone that prevents the overproduction of ketones.