You may have heard the words “Ketogenic diet” or “Keto diet” thrown around in conversation, on social media, or on TV. It likely pops up as one of the first suggestions when you search the world wide web for “best diet for weight loss.” Your friends and family may rave about it. Your favorite health influencer may swear by it. Keto cookbooks have permeated the culinary scene. “Fat Bombs” and fried butter balls are your new best friends. But what is the Ketogenic diet, really? We’re here to break down the information and serve you the facts.
What is the Ketogenic Diet?
The Ketogenic diet is a low carbohydrate, high fat diet first used in the 1920s as a treatment for epilepsy in children. The macronutrient composition of the diet is approximately 70% fat, 10-20% protein, and 5-10% carbohydrate. This means if you plan to go Keto, you will need to consume 70% of your total daily calories from fat, 10-20% from protein, and 5-10% from carbohydrates. For reference, the Dietary Guidelines for Americans recommend 20-35% of total calories come from fat, 10-35% from protein, and 45-65% from carbohydrates.
How Does it Work?
The Ketogenic diet’s combination of high fat intake and carbohydrate restriction causes the body to enter into ketosis, a metabolic state that simulates starvation. Carbohydrates break down into glucose, which is the body’s main source of fuel. When glucose becomes unavailable, the body starts to metabolize and break down fat. This, in turn, signals the liver to produce compounds from fat called ketones, which are used as an alternative energy source.
The accumulation of ketones in the blood drives the body into ketosis. This ketotic state allows the body to “burn fat.”
In other words, the body uses its own fat stores to create energy, leading to weight loss without compromising muscle mass. Increased consumption of high fat foods can also induce greater satiety, reducing appetite and total caloric intake.
What the Research Tells Us
The increasing popularity of the Ketogenic diet warrants investigation into the long-term health effects of the diet, and whether the diet is sustainable for weight loss.
Studies have shown that individuals on the Ketogenic diet initially experience rapid weight loss in the span of 1-2 weeks. Weight loss during this timeframe can reach up to 10 lbs. However, this rapid weight loss is often due to water weight, as ketones possess a diuretic effect. Regardless, there is evidence that the diet stimulates true weight loss. Several studies have found that individuals on a Ketogenic diet had significantly greater weight loss compared to individuals on a low fat diet. In one study, 50 non-diabetic obese/overweight men and women placed on the Ketogenic diet for 8 weeks had lower circulating concentrations of ghrelin, a hormone that acts as an appetite stimulant. Therefore, these individuals experienced less hunger on the Ketogenic diet and consumed less calories overall.
The Ketogenic diet has also been shown to yield short-term health benefits, such as improvements in insulin resistance, high blood pressure, elevated cholesterol and triglycerides, and HDL levels, known as the “good” cholesterol. However, the key word here is short-term. While the short-term effects have been thoroughly studied, there isn’t much literature out there on the diet’s impact on long-term health effects.
Some potential long-term side effects include hepatic steatosis, hypoproteinemia, kidney stones, osteoporosis and increased risk for gout. Vitamin and mineral deficiencies can also occur, as the Ketogenic diet excludes many different food groups. Additionally, one study found that even the short-term effects after one year were not significantly different compared to the weight loss and health benefit effects of more conventional weight loss diets.
A review of studies compared the effects of the Ketogenic diet in both rodents and humans. And the results were quite interesting. While both rodents and humans experienced early weight loss, the rodents were unable to sustain the weight loss. They also showed significant accumulation of visceral fat with worsened levels of total HDL and LDL cholesterol and triglycerides. Studies also found that rodents on the Ketogenic diet had increased glucose intolerance and decreased insulin secretion. [1, 2, 3]
The remarkable difference in health effects between humans and rodents highlights some discrepancies in human studies. Long-term rodent studies take less time to conduct than long-term human studies. This may suggest rodent studies provide a more accurate picture of the Ketogenic diet’s long-term health effects. While humans are not rodents, this does question the diet’s safety, efficacy and impact on long-term effects in humans.
Things you Need to Know before you Go Keto
In order to be effective, you need to strictly adhere to the diet’s ratio of fat, carbohydrate, and protein. This is how your body will maintain ketosis, and therefore burn fat. In reality, the diet can be challenging to follow. Eating more carbohydrate or protein than the diet allows will inhibit the process of ketosis. Note – when you eat high fat foods, your body will also use the fat you consume as energy. It doesn’t just use your fat stores. So if you are eating a very high fat diet, regardless if you are in a ketotic state, your body will utilize both what you just ate and your fat reserves. This may affect the degree of weight loss.
Furthermore, it is important to be mindful of the types of fats you are consuming. Limit the amount of saturated and trans fats, and instead opt for healthy, unsaturated fats, such as olive oil, avocados, salmon, nuts and seeds. If your body is no longer in ketosis, and you’re munching on those fat bombs or having double portions of bacon for breakfast, you may be unknowingly increasing your risk for high blood pressure and high cholesterol, which could lead to cardiovascular disease.
Be aware of the side effects. When you first start the diet, you may experience nausea, vomiting, diarrhea, constipation, headache, fatigue, dizziness, and insomnia. This is known as the Keto flu. Keto flu symptoms eventually subside as you continue the diet.
However, talk to your doctor if Keto is right for you. There are certain contraindications and at-risk individuals who should avoid the diet, or do it under close supervision of a medical team. Individuals with diabetes are at higher risk for a life-threatening condition called ketoacidosis. If taking insulin or oral hypoglycemic medications, be sure to have these medications appropriately dosed by a physician prior to starting the diet as to avoid the risk of developing severe hypoglycemia.
The Ketogenic diet is also contraindicated in certain diseases, including pancreatitis, liver failure, and disorders of fat metabolism. As previously mentioned, the diet excludes various food groups, which may put you at higher risk of nutritional deficiencies. It’s also important to remember that not everyone is cut from the same cloth. There are various other factors that can affect the diet, including level of physical activity and preexisting conditions.
The Bottom Line
The Ketogenic diet can be beneficial for weight loss, but there is still a lot we need to learn. Further studies are required to understand its safety and efficacy long-term. The diet also is difficult to sustain and requires a lot of discipline to upkeep. In terms of quality of life, a highly restrictive diet may not be the way to go. There are many ways to sustainably lose weight without sacrificing foods you enjoy. However, if you do choose to go Keto, I encourage you to consult with your medical team. Further, I encourage you to do it under the supervision of a registered dietitian. A dietitian will help you develop meal plans tailored to your specific needs. This will prevent potential nutrient deficiencies and health complications down the road.