Diets come and go, and often they come back again with just a slightly different twist and name. Such is the case with the Ketogenic diet or "Keto" for short, the newest in a line of low-carb approaches to weight loss.
A ketogenic diet is considered a very low-carbohydrate eating plan because only about five to 10 percent of your calories are coming from carbohydrates, with less than 50 grams a day being about average. The remainder of your calories come from protein, which makes up about 10 to 25 percent, and fat makes up the other 70 to 80 percent. The chart below offers a comparison of the ketogenic diet percentages to the Institute of Medicine's dietary recommendations.
| Eating Plan |
Carb % |
Protein % |
Fat % |
Institute of Medicine
(SparkPeople Plan) |
45-65% |
10-35% |
20-35% |
| Ketogenic Diet |
5-10% |
10-25% |
70-80% |
The diet's foundation lies in the fact that when carbohydrates are lacking in a person's diet, the body cannot burn fat in the correct way. Normally, carbs combine with fat fragments to be used as energy. When carbs are not available, though, there is an incomplete breakdown of fat that produces a by-product called ketone bodies. These ketones accumulate in the blood and in the urine causing ketosis. A medically managed ketogenic diet has been used for years for the treatment of epilepsy, but is today's weight-loss version a safe and appropriate eating plan?
On a ketogenic diet, you avoid all refined carbohydrates, pasta, rice, snack crackers, chips, sugary beverages, candy, cake, cookies and pastries. But in order to maintain the very low carbohydrate intake, many nutrient-rich foods are extremely limited, too, including whole grains, milk, yogurt, fruit, starchy vegetables and legumes such as beans, peas and lentils. What's left to eat? Meals and snacks are composed of meat, fish, poultry, cheese, eggs, nuts, leafy greens, some non-starchy vegetables and lots of oils and fats.
During the first week or so, a ketogenic diet brings about a rapid five- to eight-pound weight loss. But before you jump on the bandwagon, realize that the scale isn't giving you the whole story. Carbohydrate is stored in your body as a substance called glycogen. The glycogen is stored in your muscles and liver and is used for energy when needed by the body. Each gram of glycogen has two grams of water stored along with it. When you greatly restrict your carb intake, the body turns to the glycogen. With each gram of glycogen that is used, the two grams of water is also excreted from the body in your urine. Basically, your body becomes somewhat dehydrated and much of the weight change shown on your bathroom scales is water weight loss, not body fat.
In the weeks to come, the body may lose body fat slightly faster than a traditional eating plan, but the difference is minimal. Studies have shown that by a year, the weight loss is the same on a ketogenic diet compared to a more balanced eating plan. Short-term studies on a ketogenic diet have shown improvements in risk factors such as total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, blood sugar, inflammatory markers and waist circumference. However, it is important to note that any eating plan that leads to weight loss will tend to show these same types of improvements.
The Body's Immediate Reaction to the Ketogenic Diet
When there is a severe deficit of carbohydrates, the body has several immediate reactions, some favorable and some not.
Pros:
- Ketosis causes a decrease in appetite because it's one of the body's protection mechanisms, so your body will experience hunger control. It's an advantage for someone experiencing a famine (which the body thinks it's experiencing during ketosis) to have a loss of appetite because the search for food would be a waste of time and additional energy.
- No calorie counting. Your focus on keto is solely on counting the carbs, which is only in a few remaining foods in your diet.
- A possible increase in motivation and momentum due to the more rapid weight loss.
Cons:
- Nausea, headaches, dizziness, fatigue, bad breath and sleep issues due to the accumulation of ketones and the lack of energy are common in the first few weeks. Many people experience a "ketosis flu" after beginning the diet.
- Possible constipation due to the lower fiber intake can also occur.
- Difficulty in completing your normal workout routine due to the decrease in energy.
- You may also become bored with the limited food choices.
The Long-Term Effects of Keto
Evidence is not available regarding the long-term usage (more than two years) of the ketogenic diet on the overall health and wellness for humans. Therefore, there are numerous concerns to keep in mind before starting keto or any other very low-carb diet:
- Restricting nutrient-rich carbohydrate foods also restricts essential vitamins, minerals, fiber, and antioxidants found in fruits, vegetables, legumes, milk and whole grains. Key nutrients that may be lacking include calcium, fiber, folic acid, magnesium, potassium, selenium, thiamin, vitamin A, vitamin C and vitamin D.
- The risk of developing high blood pressure, heart disease, diabetes, osteoporosis and certain types of cancer increases when these healthy carbs are eliminated.
- Depending on food selection, the risk of developing gout may increase. Protein-rich foods contain purines, which are broken down into uric acid. High uric acid levels in the blood may cause uric acid crystals to build up in joints, leading to gouty arthritis.
- The risk of heart disease is increased on a long-term, very low-carb diet that is extremely high in fat, especially saturated fat.
- Beneficial gut bacteria (probiotics) feed off of certain types of fiber. A very low-carb diet, lacking in fiber, could decrease the good bacteria in your gut.
Safety Guidelines
A ketogenic diet for weight loss could be completely safe and appropriate for some adults while being disastrous and dangerous for others. As stated in the 2013 Guideline for the Management of Overweight and Obesity in Adults, numerous dietary approaches that restrict calorie intake can produce weight loss, and carbohydrate restriction is listed among these approaches.
To determine if a very low-carb diet is safe, appropriate and sustainable for you, talk first with your health care provider or registered dietitian nutritionist and obtain a personalized eating plan. Be prepared to discuss these topics in detail:
- Based on my medical conditions, what should the percentages be for carbohydrate, protein and fat? Ask for a handout of a sample meal plan, recipe ideas and reliable books or websites which incorporate these percentages. It is still important to favor lean meats and protein sources while limiting processed meats and highly saturated fat sources, such as fatty meats and cheeses, bacon, sausage, hot dogs, pepperoni, salami, deli meats, pork rinds, jerky, sour cream, cream, butter, lard, coconut oil, palm oil, chicken fat and duck fat. Use healthy fat sources such as nuts, peanuts, avocados and oils that are liquid at room temperature. For example, olive oil, canola oil, soybean oil, corn oil, safflower oil and sunflower oil are all great options.
- How long am I able to safely use the diet?
- When and how do I transition my diet to include more carb-containing foods?
- Does the eating plan fit with my cultural, food preference and food budget needs?
- Can I follow this eating plan for the rest of my life?
The bottom line: When it comes to the latest, greatest diet, who doesn't love sensationalism? It used to be "fats bad, carbs good," now it's "fats good, carbs bad." Come on, folks, let's get serious. "All or nothing" eating plans are silly, unrealistic and bring about feelings of guilt, frustration and failure.
While research has given us many answers regarding the role of carbohydrate, fat and protein on health and body weight, there are still unanswered areas to address. As we wait for well-designed randomized control trials to bring more clarity regarding this debate, it's best to stick with a calorie-controlled eating plan based on research evidence, such as the: DASH Diet, Mediterranean Diet, Choose My Plate or the Smart Carb-Shoddy Carb Plan.
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