The ketogenic diet is trending and has been for the last three years as more and more blogs and cookbooks continue to pop up. The diet has been used under close supervision by physicians and dietitians since the 1920s for treating epilepsy and has shown promise in managing brain cancer. But in this ketogenic diet review, weight loss, safety and more will be analyzed based on the current research. You’ll finally find out if the keto diet is useful and healthy as a weight loss diet.
What is the ketogenic diet?
Fat makes your meals more palatable and helps you feel full, so it’s no wonder the high fat ketogenic diet is increasing in popularity. Fat has more than double the amount of calories than protein or carbohydrate, so it seems counterintuitive that eating as much fat as you want could help you lose weight. The catch is you have to also restrict carbohydrates or you’ll be gaining weight instead of losing it.
The ketogenic diet has 70% or more of your daily calories coming from fat. It’s also very low in carbohydrates, defined in the literature as 20-50 grams of carbs a day. This works out to only 5-10% of your daily calories from carbohydrates and that leaves up to 25% of your daily energy from protein. Compare this to a healthy diet recommended by the Institute of Medicine: 45-65% carbs, 20 to 35% fat and 10 to 35% protein (check and link). 45 to 65 percent carbs, 20 to 35 percent fat and 10 to 35 percent protein.
The ketogenic diet’s low carb target can only be met by avoiding grains, dairy products, fruit and legumes such as chickpeas and lentils. Starchy vegetables such as sweet potatoes and squash are out, and even the lower carb vegetables are limited.
So what’s left to eat? A typical day on the “keto diet” consists of eggs, avocado and butter for breakfast, salad with meat or fish and plenty of oil for lunch and dinner.
What is ketosis?
Several days of fasting or limiting carbohydrates to 50 grams a day or less causes your body to use up all of the stored carbohydrate in your muscles and liver. Once that runs out, your brain looks elsewhere for it’s favorite fuel: glucose.
Your body adapts to low carb diets by breaking down fat and protein and converting a portion of them into glucose. Compounds called ketone bodies are produced that are used by your muscles, brain and other tissues for energy.
How the ketogenic diet works
One of the most challenging aspects of sticking to a diet is feeling hungry. Research on the ketogenic diet suggests that the production of ketone bodies lowers your ghrelin levels, a hormone that makes you hungry. Essentially, you’ll find you’re able to stay satisfied for longer on this diet.
When you limit carbohydrates in your diet, the stored carbohydrate in your muscles and liver (called glycogen) is depleted. Glycogen is stored with water, so restricting carbs famously helps you lose weight quickly by causing you to lose water weight. As soon as you start eating carbohydrates again, the water weight will come right back on. However, this early weight loss can help motivate people to continue with the diet.
If you remove foods from your diet that you love and start to limit your diet, you’re going to lose weight. Some people find it easier to avoid worrying about calories and portion sizes and to have a list of foods they can eat as much as they want of. That’s one of the reasons why the ketogenic diet works.
The majority of studies and systematic reviews on the ketogenic diet have found that following it from anywhere between 3 months up to 3 years significantly improves levels of triglycerides and high-density lipoprotein (HDL) cholesterol and increases the size of low-density lipoprotein (LDL) cholesterol particles, lowering heart disease risk. Studies have also shown the keto diet reduces blood sugar, insulin, C-reactive protein (a marker of inflammation) and waist circumference.
While these results seem impressive, any weight loss diet will result in improvements in metabolic risk factors. The real question is, how does the keto diet hold up against diets that contain higher amounts of healthy carbohydrates?
Does the ketogenic diet lead to faster weight loss?
Here’s what the research suggests so far:
A study comparing the impact of a ketogenic diet (less than 20 grams of carbohydrates a day) to a low glycemic index diet (reducing calories by 500 a day) on weight loss in obese individuals with type 2 diabetes found that after 6 months, the keto diet group lost an average of 24.5 lbs compared to the low glycemic index group who lost 15.2 pounds on average. While these results seem promising, inquiring minds want to know… what happened after the 6 months? Did people regain the weight?
A fascinating study investigating whether following a keto diet boosts metabolism put 17 overweight and obese men on a higher carb diet for 4 weeks followed by 4 weeks on a ketogenic diet with the same amount of calories. The men spent 2 consecutive days a week in a metabolic chamber that measured the energy they burned. While slightly more calories were burned during the ketogenic diet (57-89 extra calories a day), fat loss actually slowed down as the body used protein and broke down muscle for energy. Losing muscle slows down your metabolism in the long-run, making this diet a poor choice for anyone wanting to be strong and lean.
A Brazilian meta-analysis of randomized control trials of a year or longer found that people on a ketogenic diet lost an average of 2 lbs more after a year and improved their triglycerides, HDL and blood pressure compared to those on a low fat diet (less than 30% of calories).
When the researchers looked at studies that followed participants for 2 years, they found that HDL improved more in the keto diet group but there was no difference in weight loss between the groups. Many study participants weren’t able to maintain the keto diet targets for long, with carbohydrates averaging 36-190 grams a day or 33-47% of calories by the end of the studies (compared to the goal of less than 50 grams of carbohydrates a day or 5-10% of calories). The researchers also pointed out that measures of safety such as kidney and liver function weren’t taken in these studies.
The ketogenic diet and exercise
Personally, restricting my carbohydrates for even a couple of days makes me barely able to get through my day let alone my workouts. There is some evidence that the ketogenic diet lowers strength and aerobic capacity but no more than being on a low fat diet. Interestingly, the keto diet does seem to help people burn a higher percentage of fat during workouts. Who would have thought eating fat helps you burn more fat?
Why you shouldn’t try the ketogenic diet
Typically there is a concern with high protein diets adding strain on the kidneys, but the keto diet is a high fat diet rather than a high protein diet. However, the ketogenic diet hasn’t been studied in people with impaired kidney function, so it’s best avoided if you have kidney problems.
As with other low carbohydrate diets, getting enough fiber is difficult on the ketogenic diet. The result? Constipation and increased risk of colorectal cancer.
The ketogenic diet can also be deficient in calcium, vitamin D, vitamin C and vitamin A, so be sure to consult with a registered dietitian to ensure you’re meeting your nutrient needs, especially if you’re planning to follow this diet for more than a couple of weeks.
The Bottom Line:
My ketogenic diet review: weight loss will happen, but it’s tough to sustain
Low carb diets seem to be more effective than other diets over 6 months, but after a year, they become less effective. As researchers have stated, any benefits of the ketogenic diet aren’t clinically significant, meaning any advantages over other diets are too small to make a difference in your life.
Consider how following such a restrictive diet will affect your quality of life and enjoyment of food. It can be tough to limit your food choices over the long term. And as mentioned, as soon as you start eating carbohydrates again, the water weight will come right back on.
People who feel more energized on lower carb diets and enjoy eating fats and oils could do well on the ketogenic diet. Anyone like me who loves their fruit, whole grains and vegetables (me, for example) will struggle to avoid their favorite foods. Choose the eating plan that fits your likes and patterns best.
If you want to try the ketogenic diet, see a dietitian first to make sure you’re meeting your nutrient needs. Also, be sure to tell your doctor about your diet and get regular check ups if you’re on any medications for blood sugar, blood pressure or cholesterol. As you lose weight, your dosages will likely be adjusted. Only adjust your medications under close supervision by your doctor.
The best diet is one you can stick to that will boost your overall health and won’t leave you feeling energy zapped and anti-social in the process. That’s my ketogenic diet review and I’m sticking to it!