The Ketogenic diet, also known as the “keto” diet has become very popular over the years with it being named the most popular diet by Shape magazine in 2018. You have probably seen many advertisements, health claims, and even heard testimonials from your closest friends on the benefits of the keto diet. This diet has become so popular; it is a phenomenon that has influenced restaurants and eateries to offer keto diet options.
So is all of the hype around this diet legitimate?
1. WHAT IS THE KETO DIET?
The keto diet is essentially a low-carbohydrate, fat-rich diet.
Despite its recent popularity, this diet has actually been used for centuries to treat medical conditions including helping to control diabetes and treating children with epilepsy. Interestingly enough this diet has recently gained a lot of attention for its potential weight loss effects.
The difference between the keto diet and other low-carb diets such as the Atkins diet (a low-carb, high protein diet), the Paleo diet, and South Beach diet, is its exceptionally high-fat content.
According to the Food and Nutrition Board of Institutes of Medicine, the acceptable macronutrient distribution range in a regular diet is carbohydrates (45-65% of energy), protein (10-35% of energy), and fat (20-35% of energy; limit saturated and trans fats) . While there are several versions of the keto diet, the standard version for macronutrient ranges are 70-80% of fat, 10-20% of protein, and 5-10% of carbohydrate .
2. HOW DOES IT WORK?
The main energy source for all cells of the body is glucose, which is obtained from eating carbohydrates. The weight loss effects of the ketogenic diet is based on the idea that depriving your body glucose will cause your body to use an alternative fuel, called ketones, which is produced from stored fat (hence the name “keto-genic” diet).
When you eat a very low carbohydrate diet, the body takes stored glucose from the liver and temporarily breaks down muscle to release glucose in order to meet the body’s demand. The brain is one of the body’s organs that require constant need of glucose because it is unable to store glucose. If your body continues to be deprived of glucose for 3-4 days, and all glucose stores are depleted, the body will decrease production of a hormone called insulin, and start to use fat as its primary fuel .
The ketogenic diet is based on depriving the body carbohydrates so that the metabolism remains in a ketotic state. It is important to note that protein can also interfere with ketosis as well, which means that fat is the primary food group in this diet.
Ketones produced by the body can be utilized for energy production by the heart, muscles, and kidneys in the absence of glucose. While red blood cell’s and the liver are unable to use ketones for energy, ketone bodies are able to pass through the blood-brain barrier to provide an alternative energy source for the brain.
The accumulation of ketone bodies in the blood is called ketosis. For healthy individuals, it is natural to experience mild ketosis while fasting (i.e. sleeping over night, or a skipped meal), as well as during very strenuous exercise. This metabolic state is referred to as “nutritional ketosis,” which is considered safe because ketone bodies are produced in small concentrations and do not alter blood pH levels. This type of ketosis is very different from ketoacidosis, which is a life-threatening condition where large amounts of ketone bodies are produced, altering blood pH levels to an acidic state .
According to Harvard Health, the rate at which ketosis can happen including the number of ketone bodies that accumulate in the blood is variable from each person and depends on factors such as body fat percentage and resting metabolic rate. Ketoacidosis is most common in individuals who have type I diabetes, though following a prolonged low-carbohydrate diet can also cause ketoacidosis in non-diabetic individuals .
3. BENEFITS OF KETO DIET
The ketogenic diet has been shown to produce many beneficial health changes in the short term. Many individuals on a ketogenic diet experience rapid weight loss up to 10 lbs. in 2 weeks . This diet has a diuretic effect; meaning initial weight loss is most likely due to water weight loss, though fat loss will follow. It has been found that the ketogenic diet spares lean body muscle, which is especially important for athletes or individuals who are trying to build lean body mass .
Fatty foods tend to be more filling and satiating, therefore many individuals find that during nutritional ketosis, hunger pains subside, and overall calorie intake is reduced, which also helps further weight loss. Many people also experience improvements in their cholesterol, blood pressure, and blood sugar levels. Additionally, ketone bodies produce more energy in comparison to glucose, which allows the body to maintain efficient energy even during a caloric deficit .
Research is ongoing on the benefits that the ketogenic diet may have on insulin sensitivity for individuals who have pre-diabetes and diabetes. Studies also continue to find the helpful effects that ketone bodies have on decreasing free radical damage and enhancing antioxidant capacity, including reducing inflammation [3,5].
While the exact theory on why the ketogenic diet seems to be so effective is unknown, here are some promising theories:
- Decreased food cravings due to high fat content of diet, also known as the satiating effect .
- Eating a restricted amount of carbohydrates decreases your hunger hormones such as insulin and ghrelin .
- Converting fat and protein to energy requires more energy, hence increased energy expenditure .
- Due to decreased insulin levels, fat loss and lean body mass increase .
4. KETO DIET GUIDE
There are many versions of the keto diet, however all forms restrict carb-rich foods.
The standard ketogenic diet typically reduces carbohydrate intake to less than 50 grams per day and can be as low as 20 grams per day . While there are several versions of the keto diet, the standard version for macronutrients ranges consists of:
- 70-80% of fat
- 10-20% of protein
- 5-10% of carbohydrate.
For a 2,000 kcal diet, this equates to about 165 g fat, 40 g carbs, and 75 g protein.
Protein is kept at a minimum to prevent the body from converting it into glucose. The amount of protein in a ketogenic diet should be enough to prevent the loss of any lean body mass, but still maintain ketosis.
Due to the high fat content, this diet is very satiating, which means people typically lose weight without having to count calories.
Most keto diets suggest continuing the diet until the desired amount of weight is lost. However, research studies suggest that the diet be followed for a minimum of 2 to 3 weeks up to 6 to 12 months to limit any long-term adverse effects.
In order to prevent weight gain, the transition to a standard diet should be gradual and well controlled. In order to maintain control, one may choose to follow the keto diet for a few days a week or a few weeks a month [2,3].
If you are interested in starting the keto diet, here are some important points to remember:
- This diet has a strong emphasis on fats at each meal as well as snacks in order to meet the high-fat requirements. It is important to choose foods that are high in healthy fats such as polyunsaturated and monounsaturated fats. Even though saturated fats are allowed on this diet, it should be restricted to limit any negative long-term health effects.
- Some dairy foods may be allowed. Dairy foods are a great source of fat and vitamins, however they are also naturally high in lactose sugar (i.e. cream, ice cream, and full-fat milk). Butter, and hard cheeses are allowed on the ketogenic diet due to its lower lactose content.
- In order to maintain ketosis, protein must be consumed in moderation. Choose meat products that are grass-fed (not grain-fed), and free range in order to get higher amounts of omega-3 fatty acids.
- Choose non-starchy vegetables. There are a lot of vegetable options that are low in carbs such as leafy greens, cauliflower, broccoli, Brussels sprouts, bell peppers, and cucumbers.
- Small portions of fruit such as berries are allowed, due to its lower “net carbs.”
Here is a list of keto diet approved foods for your grocery list:
- Seafood: Salmon, sardines, mackerel, trout, tuna, other fatty fish.
- Meat: red meat, steak, ham, sausage, bacon, chicken, and turkey.
- Eggs: choose pasture-raised, or free-range whole eggs.
- Dairy products: butter, unprocessed cheese (gouda, cheddar, blue, or mozzarella).
- Nuts/seeds: almonds, walnuts, flax seeds, pumpkin seeds, chia seeds.
- Oils: extra virgin olive oil, avocado oil, coconut oil.
- Fruit: avocados, berries (small portion).
- Low-carb vegetables: kale, Swiss chard, spinach, bok choy, lettuces, cauliflower, bell peppers, onions, mushrooms, cucumber, celery, summer squashes, broccoli, Brussels sprouts, tomatoes.
- Condiments: salt, pepper, herbs, and spices.
Here are foods that you should avoid while on the keto diet:
- Whole/refined grain and flour products: rice, pasta, cereal, wheat-based products,
- Added and natural sugars: candy, soda, fruit juice, and baked goods.
- Fruits: all fruit, except small portions of berries.
- Legumes: beans, lentils, peanuts, chickpeas.
- Starchy and root vegetables: potatoes, corn, peas, carrots, parsnips and winter squash.
- Alcohol and sugary drinks including smoothies, and fruit juice.
- Low fat or diet products: these produces are highly processed and often high in carbs or added sugars.
- Condiments: sauces or condiments that contain high amounts of sugar or saturated fats.
- Unhealthy fats: limit intake of mayonnaise, or processed vegetable oils.
- Sugar-free foods: besides being highly processed, these products are often high in sugar alcohols, which can affect ketosis in some cases.
5. KETO DIET MEALS
Learning how to cook a keto friendly meal can be difficult. Here are keto diet meal suggestions for you to try.
- Bacon, eggs, and tomatoes
- Egg, tomato, spinach, and feta cheese omelet
- Plain Greek yogurt with peanut butter, cocoa powder, and berries
- Spanish omelet with bell peppers, onions, and avocado
- Chicken salad made with avocado, olive, oil and feta cheese
- Beef stir fry with vegetables and Shirataki noodles
- Slices of cheese, slices of salami, olives, and nuts
- Burger with cheese and guacamole
- Steak and eggs with side of peppers or salad
- Salmon and Brussels sprouts
- Ground turkey lettuce wrap
- Pork chops with broccoli and cauliflower
- Nuts and cheese
- Baked avocado with egg
- Beef jerky
- Olives and seeds
- Hard boiled egg
- Strawberries and cream
6. RISKS OF KETO DIET
One of the biggest concerns regarding the keto diet is maintaining a diet with such a high fat content. Long-term compliance with the keto diet is very low. Due to the extreme carbohydrate restrictions, the following symptoms may occur and last anywhere from days to weeks:
- Low mood
- Brain “fog”
- “Keto flu”
It is imperative that adequate fluid and electrolytes are taken to help combat some of the short-term symptoms. The long-term health implications of the keto diet are still unknown. However, the keto diet may increase your risk of these long-term adverse effects:
- Kidney stones [2,3]
- Hypoproteinemia (low level of protein in blood) [2,3]
- Hepatic steatosis (accumulation of fat in the liver) [2,3]
- Osteoporosis [2,3]
- Increased levels of uric acid (risk of gout) [2,3]
- Vitamin and mineral deficiencies: selenium, magnesium, phosphorus, vitamins B and C [2,3]
Eliminating several food groups makes this diet very difficult to adhere to. Since the keto diet places an emphasis on fats, many individuals choose foods that are high in saturated fats, which may have a negative impact on cholesterol and heart health in the long-term. Even though the keto diet is significantly better in initiating weight loss in healthy individuals, the metabolic health benefits are short term. Unfortunately, the health improvements experienced from the keto diet after one year is not significantly different from the effects of conventional weight loss . More short and long term studies need to be performed in order to fully understand the impacts, safety, and efficacy of the keto diet.
There is no doubt that the ketogenic diet is very popular, despite any research supporting its long-term success. The ketogenic diet is a great option for individuals who have had a difficult time losing weight with other methods.
The balanced ratio of carbohydrates, fat, and protein needed to achieve healthy benefits is very tricky to follow and should be monitored by a physician or registered dietitian. If followed appropriately, this diet can provide effective results.
However, the proper meal plan must be tailored to the individual’s needs with consideration of one’s existing health conditions, genetic makeup, and body composition to prevent nutritional deficiencies and other health complications.
Furthermore, a registered dietitian may also provide guidance on reintroduction of carbohydrates once the desired amount of weight loss is attained.