The ketogenic diet, characterized by a very low carbohydrate intake and high fat consumption, has gained popularity for its potential health benefits, including weight loss and improved management of certain diseases. This article delves into the specifics of the keto diet, exploring its various types, mechanisms, benefits, risks, and how to implement it effectively, with a special focus on the keto-green approach.
Keto Basics: Shifting the Body's Fuel Source
The ketogenic diet (or keto diet, for short) is a low carb, high fat diet that offers many health benefits. The ketogenic diet is a very low carb, high fat diet that shares many similarities with the Atkins and low carb diets. It involves drastically reducing carbohydrate intake and replacing it with fat. This reduction in carbs puts your body into a metabolic state called ketosis. When this happens, your body becomes incredibly efficient at burning fat for energy. It also turns fat into ketones in the liver, which can supply energy for the brain (6). Ketogenic diets can cause significant reductions in blood sugar and insulin levels. This, along with the increased ketones, has some health benefits (6, 7, 8).
Types of Ketogenic Diets
There are several versions of the ketogenic diet, and what you eat depends on the type. They include:
- Standard Ketogenic Diet (SKD): This is a very low carb, moderate protein and high fat diet. It typically contains 70% fat, 20% protein, and only 10% carbs (9).
- Cyclical Ketogenic Diet (CKD): This diet involves periods of higher carb refeeds, such as 5 ketogenic days followed by 2 high carb days.
- Targeted Ketogenic Diet (TKD): This diet allows you to add carbs around workouts.
- High Protein Ketogenic Diet: This is similar to a standard ketogenic diet, but includes more protein. The ratio is often 60% fat, 35% protein, and 5% carbs.
However, only the standard and high protein ketogenic diets have been studied extensively. Cyclical or targeted ketogenic diets are more advanced methods and primarily used by bodybuilders or athletes. The information in this article mostly applies to the standard ketogenic diet (SKD), although many of the same principles also apply to the other versions.
Achieving Ketosis: The Metabolic Switch
Ketosis is a metabolic state in which your body uses fat for fuel instead of carbs. It occurs when you significantly reduce your consumption of carbohydrates, limiting your body’s supply of glucose (sugar), which is the main source of energy for the cells. Following a ketogenic diet is the most effective way to enter ketosis. Generally, this involves limiting carb consumption to around 20 to 50 grams per day and filling up on fats, such as meat, fish, eggs, nuts, and healthy oils (6). It’s also important to moderate your protein consumption. This is because protein can be converted into glucose if consumed in high amounts, which may slow your transition into ketosis (10). Practicing intermittent fasting could also help you enter ketosis faster. There are many different forms of intermittent fasting, but the most common method involves limiting food intake to around 8 hours per day and fasting for the remaining 16 hours (11). Blood, urine, and breath tests are available, which can help determine whether you’ve entered ketosis by measuring the amount of ketones produced by your body. Certain symptoms may also indicate that you’ve entered ketosis, including increased thirst, dry mouth, frequent urination, and decreased hunger or appetite (12).
Read also: Easy Low-Carb Cheese Crackers
Health Benefits of the Ketogenic Diet
A ketogenic diet is an effective way to lose weight and lower risk factors for disease (1, 2, 3, 4, 5). In fact, research shows that the ketogenic diet may be as effective for weight loss as a low fat diet (13, 14, 15). What’s more, the diet is so filling that you can lose weight without counting calories or tracking your food intake (16). One review of 13 studies found that following a very low carb, ketogenic diet was slightly more effective for long-term weight loss than a low fat diet. People who followed the keto diet lost an average of 2 pounds (0.9 kg) more than the group that followed a low fat diet (13). Another study in 34 older adults found that those who followed a ketogenic diet for 8 weeks lost nearly five times as much total body fat as those who followed a low fat diet (17). The increased ketones, lower blood sugar levels, and improved insulin sensitivity may also play a key role (18, 19).
Diabetes Management
Diabetes is characterized by changes in metabolism, high blood sugar, and impaired insulin function (20). One older study found that the ketogenic diet improved insulin sensitivity by a whopping 75% (25). A small study in women with type 2 diabetes also found that following a ketogenic diet for 90 days significantly reduced levels of hemoglobin A1C, which is a measure of long-term blood sugar management (26). Another study in 349 people with type 2 diabetes found that those who followed a ketogenic diet lost an average of 26.2 pounds (11.9 kg) over a 2-year period. This is an important benefit when considering the link between weight and type 2 diabetes (24, 27). What’s more, they also experienced improved blood sugar management, and the use of certain blood sugar medications decreased among participants throughout the course of the study (27).
Other Health Conditions
Studies have now shown that the diet can have benefits for a wide variety of different health conditions:
- Heart disease: The ketogenic diet can help improve risk factors like body fat, HDL (good) cholesterol levels, blood pressure, and blood sugar (28, 29).
- Cancer: The diet is currently being explored as an additional treatment for cancer, because it may help slow tumor growth. (4, 30, 31).
- Alzheimer’s disease: The keto diet may help reduce symptoms of Alzheimer’s disease and slow its progression (5, 32, 33).
- Epilepsy: Research has shown that the ketogenic diet can cause significant reductions in seizures in epileptic children (3).
- Parkinson’s disease: Although more research is needed, one study found that the diet helped improve symptoms of Parkinson’s disease (34).
- Polycystic ovary syndrome: The ketogenic diet can help reduce insulin levels, which may play a key role in polycystic ovary syndrome (35, 36).
- Brain injuries: Some research suggests that the diet could improve outcomes of traumatic brain injuries (37).
However, keep in mind that research into many of these areas is far from conclusive.
Foods to Eat and Avoid on a Ketogenic Diet
Here’s a list of foods that need to be reduced or eliminated on a ketogenic diet:
Read also: Keto Calorie Counting: A Detailed Guide
- Sugary foods: soda, fruit juice, smoothies, cake, ice cream, candy, etc.
- Grains or starches: wheat-based products, rice, pasta, cereal, etc.
- Fruit: all fruit, except small portions of berries or strawberries
- Beans or legumes: peas, kidney beans, lentils, chickpeas, etc.
- Root vegetables and tubers: potatoes, sweet potatoes, carrots, parsnips, etc.
- Low fat or diet products: low fat mayonnaise, salad dressings, and condiments
- Some condiments or sauces: barbecue sauce, honey mustard, teriyaki sauce, ketchup, etc.
- Unhealthy fats: processed vegetable oils, mayonnaise, etc.
- Alcohol: beer, wine, liquor, mixed drinks
- Sugar-free diet foods: sugar-free candies, syrups, puddings, sweeteners, desserts, etc.
You should base the majority of your meals around these foods:
- Meat: red meat, steak, ham, sausage, bacon, chicken, and turkey
- Fatty fish: salmon, trout, tuna, and mackerel
- Eggs: pastured or omega-3 whole eggs
- Butter and cream: grass-fed butter and heavy cream
- Cheese: unprocessed cheeses like cheddar, goat, cream, blue, or mozzarella
- Nuts and seeds: almonds, walnuts, flaxseeds, pumpkin seeds, chia seeds, etc.
- Healthy oils: extra virgin olive oil, and avocado oil
- Avocados: whole avocados or freshly made guacamole
- Low carb veggies: green veggies, tomatoes, onions, peppers, etc.
- Condiments: salt, pepper, herbs, and spices
It’s best to base your diet mostly on whole, single-ingredient foods.
Sample Keto Meal Plan
Here is a sample ketogenic diet meal plan for one week:
Monday
- Breakfast: veggie and egg muffins with tomatoes
- Lunch: chicken salad with olive oil, feta cheese, olives, and a side salad
- Dinner: salmon with asparagus cooked in butter
Tuesday
Read also: Magnesium Supplements for Keto
- Breakfast: egg, tomato, basil, and spinach omelet
- Lunch: almond milk, peanut butter, spinach, cocoa powder, and stevia milkshake (more keto smoothies here) with a side of sliced strawberries
- Dinner: cheese-shell tacos with salsa
Wednesday
- Breakfast: nut milk chia pudding topped with coconut and blackberries
- Lunch: avocado shrimp salad
- Dinner: pork chops with Parmesan cheese, broccoli, and salad
Thursday
- Breakfast: omelet with avocado, salsa, peppers, onion, and spices
- Lunch: a handful of nuts and celery sticks with guacamole and salsa
- Dinner: chicken stuffed with pesto and cream cheese, and a side of grilled zucchini
Friday
- Breakfast: sugar-free Greek, whole milk yogurt with peanut butter, cocoa powder, and berries
- Lunch: ground beef lettuce wrap tacos with sliced bell peppers
- Dinner: loaded cauliflower and mixed veggies
Saturday
- Breakfast: cream cheese pancakes with blueberries and a side of grilled mushrooms
- Lunch: Zucchini and beet “noodle” salad
- Dinner: white fish cooked in olive oil with kale and toasted pine nuts
Sunday
- Breakfast: fried eggs with and mushrooms
- Lunch: low carb sesame chicken and broccoli
- Dinner: spaghetti squash Bolognese
Always try to rotate the vegetables and meat over the long term, as each type provides different nutrients and health benefits.
Eating Out on Keto
When eating out, select a meat-, fish-, or egg-based dish. Order extra veggies instead of carbs or starches, and have cheese for dessert. Egg-based meals are also a great option, such as an omelet or eggs and bacon. Another favorite is bun-less burgers. You could also swap the fries for vegetables instead. Add extra avocado, cheese, bacon, or eggs. At Mexican restaurants, you can enjoy any type of meat with extra cheese, guacamole, salsa, and sour cream. For dessert, ask for a mixed cheese board or berries with cream.
Potential Side Effects and How to Minimize Them
Although the ketogenic diet is usually safe for most healthy people, there may be some initial side effects while your body adapts. There’s some anecdotal evidence of these effects often referred to as the keto flu (38). Based on reports from some on the eating plan, it’s usually over within a few days. Reported keto flu symptoms include diarrhea, constipation, and vomiting (39). Other less common symptoms include:
- Poor energy and mental function
- Increased hunger
- Sleep issues
- Nausea
- Digestive discomfort
- Decreased exercise performance
To minimize this, you can try a regular low carb diet for the first few weeks. This may teach your body to burn more fat before you completely eliminate carbs. A ketogenic diet can also change the water and mineral balance of your body, so adding extra salt to your meals or taking mineral supplements may help. Talk to your doctor about your nutritional needs. At least in the beginning, it’s important to eat until you’re full and avoid restricting calories too much. Usually, a ketogenic diet causes weight loss without intentional calorie restriction.
Long-Term Considerations
While the keto diet has its benefits, staying on it in the long term may have some negative effects, including risks of the following:
- Low protein in the blood
- Extra fat in the liver
- Kidney stones
- Micronutrient deficiencies
A type of medication called sodium-glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes can increase the risk for diabetic ketoacidosis, a dangerous condition that increases blood acidity. Anyone taking this medication should avoid the keto diet (40, 41). More research is being done to determine the safety of the keto diet in the long term. Keep your doctor informed of your eating plan to guide your choices.
Helpful Supplements for Keto
Although no supplements are required, some can be useful.
- MCT oil: Added to drinks or yogurt, MCT oil provides energy and helps increase ketone levels.
- Minerals: Added salt and other minerals can be important when starting out due to shifts in water and mineral balance (44).
- Caffeine: Caffeine can have benefits for energy, fat loss, and performance (45).
- Exogenous ketones: This supplement may help raise the body’s ketone levels (46).
- Creatine: Creatine provides numerous benefits for health and performance. This can help if you are combining a ketogenic diet with exercise (47).
- Whey: Use half a scoop of whey protein in shakes or yogurt to increase your daily protein intake (48, 49).
Addressing Common Concerns
- Can I ever eat carbs again? Yes. However, it’s important to significantly reduce your carb intake initially. After the first 2 to 3 months, you can eat carbs on special occasions - just return to the diet immediately after.
- Will I lose muscle? There’s a risk of losing some muscle on any diet. However, protein intake and high ketone levels may help minimize muscle loss, especially if you lift weights (50, 51).
- Can I build muscle on a ketogenic diet? Yes, but it may not work as well as on a moderate carb diet (52, 53).
The Keto-Green Diet: A Balanced Approach
The Keto-Green diet combines the principles of the ketogenic diet with alkaline-promoting foods. This approach aims to mitigate some of the potential drawbacks of traditional keto, such as the "keto flu" and nutrient deficiencies, while enhancing its benefits.
Principles of the Keto-Green Diet
- Prioritize Alkaline Foods: Emphasizes consumption of alkaline vegetables, especially low-carb green veggies.
- Test, Don't Guess: Advocates for regular urine pH testing to maintain a pH between 7 and 8.
- Modified Macronutrient Ratios: Follows a specific plate image and macronutrient ratio that favors alkaline and plant-based foods.
Key Differences from Traditional Keto
- Focus on Plant Foods: Favors alkaline and plant foods such as green leafy vegetables and other low-calorie veggies.
- Testing: Encourages testing of urine ketones and alkalinity (pH).
Implementing the Keto-Green Diet
- Start with a Detox: Begin with a 10-Day Keto-Green Detox to kickstart weight loss and alkalinity.
- Progress to a 21-Day Plan: Follow a structured 21-Day Keto-Green Diet plan with specific meal plans and lifestyle tips.
- Incorporate Keto-Green Shakes: Utilize Keto-Green shake powders with MCT oil, green powdered supplements, and water.
Foods to Emphasize on Keto-Green
- Green Vegetables: Prioritize low-carb green vegetables for their alkalinity and nutrient density.
- Healthy Fats: Include sources like avocados, nuts, seeds, and olive oil.
- Clean Protein: Opt for grass-fed, free-range, and wild-caught sources of protein.
Foods to Limit or Avoid
- Starchy Vegetables: Limit sweet potatoes, beets, and squash due to their high carb content.
- Whole Grains: Avoid grains like rice and quinoa, which can quickly exceed carb limits.
- Legumes: Skip lentils, black beans, kidney beans, and peanuts due to their high starch content.
- High-Sugar Fruits: Limit or avoid fruits like blueberries, cantaloupe, grapes, oranges, peaches, plums, and tropical fruits.
- Processed Meats: Be cautious with cold cuts that may contain gluten, artificial sweeteners, and preservatives.
- Unhealthy Fats: Stay away from hydrogenated trans fats like margarine.
Potential Benefits of Keto-Green
- Hormone Balance: Aims to balance hormones responsible for increased belly fat.
- Reduced Inflammation: Promotes alkaline foods to combat inflammation.
- Improved Weight Loss: Supports weight loss by maintaining a fat-burning state.
The Microbiome and Ketogenic Diet
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 [13]. 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. These bacteria can alter our response to different food sources because they differ in their ability to harvest energy from food, affecting the postprandial glucose response (PPGR) [13]. Since the controlling of glucose levels in the blood seems to reduce the risk of metabolic disease, diabetes, and obesity, this might be an innovative way to help reduce disease risk.
Impact of Diet on Microbiome Diversity
According to a study conducted by Rothschild et al. [15], the average heritability of the gut microbiome taxa is only 1.9%, while over 20% of variability was associated with diet and lifestyle. Thus, research into the complex interactions that exist between diet, the microbiome, and host metabolic rates have increased. Discovering how the gut microbiota and diet interact and how this interaction is connected to overall health, is critical. It is important to determine whether new dietary changes, such as a ketogenic diet, will positively or negatively affect overall microbiome diversity and species make-up.
Potential Effects of Keto on the Microbiome
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. Studies have shown that a low ratio of Firmicutes to Bacteroidetes is an indicator of a healthy microbiome [26]. Therefore, it appears that reducing obesity with the KD may result in positive changes in the microbiome.
Epigenetics and the Ketogenic Diet
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 [20]. The modifications of the genome involve DNA methylation, changes to chromatin structure, histone modification, and noncoding RNAs.
How Keto Impacts Epigenetics
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 [20]. 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 [20].
Ketosis and Oxidative Stress
A literature review by Miller et al. [23] 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 [23].