Do the pros of the ketogenic diet outweigh the cons? For me, they don’t. Here's why. Read the transcript at https://www.quickanddirtytips.com/health-fitness/weight-loss/pros-and-cons-of-the-ketogenic-diet Check out all the Quick and Dirty Tips shows: www.quickanddirtytips.com/podcasts FOLLOW NUTRITION DIVA Facebook: https://www.facebook.com/QDTNutrition/ Twitter: https://twitter.com/NutritionDiva
Do the pros of the ketogenic diet outweigh the cons? For me, they don’t. Here's why.
Read the transcript at https://www.quickanddirtytips.com/health-fitness/weight-loss/pros-and-cons-of-the-ketogenic-diet
Check out all the Quick and Dirty Tips shows:
www.quickanddirtytips.com/podcasts
FOLLOW NUTRITION DIVA
Facebook: https://www.facebook.com/QDTNutrition/
Twitter: https://twitter.com/NutritionDiva
Long-time listeners of the Nutrition Diva podcast might recall an episode I did in 2013 in which I briefly mentioned the ketogenic diet. I didn’t get into too many details about the diet; I was talking about how two people can get similar results following diametrically opposed strategies. (Also, about the extremes that some people go to in order to lose weight!)
As I said back then, the ketogenic diet deserves an episode of its own. In the five years it’s taken me to make good on that promise, the ketogenic diet has gone from a fringe fad diet to a mainstream fad diet! Every week, I get questions from listeners about what this diet is, whether it’s effective, and whether it’s safe.
Not that you have to ask me to get answers to these questions! I’m sure that there are several people in your office, at your gym, in your carpool, and around your Thanksgiving table that can give you their opinion, based on personal experience or stuff they read on the internet. But here, better late than never, is a perspective based on the evidence—such as it is.
One of the reasons it has taken me so long to venture into this topic more fully is that the evidence on the ketogenic diet for weight loss has been pretty skimpy.
This diet has been very well-researched as a therapy for epilepsy. Although it can be very effective in preventing seizures, it is usually conducted under strict medical supervision. And not just because epilepsy is a serious condition. Until more recently, the ketogenic diet was considered far too extreme and potentially risky to recommend for general use.
Now, it is one of the fastest growing diet and weight loss trends, touted in best-selling diet books and by celebrities, personal trainers, and other people that you might not necessarily want to take medical advice from.
Since the ketogenic diet has become so popular, the meaning of the term has also become somewhat diluted. Many people say they are "eating keto" because they choose “keto-friendly” snack foods or energy bars, or take the top bun off their burgers. A true ketogenic diet is extremely low in carbohydrates, usually less than 50 grams per day, or about 10% of calories. (The typical diet contains four to five times that much.)
The idea is to eat so few carbs that it forces your body into a state of ketosis. Instead of using glucose from your food or glycogen from your muscle to fuel biological processes, your body will turn fat into an alternate source of energy called ketones. For those tissues and organs that can’t utilize ketones, the body also has a way of turning amino acids from protein into glucose.
One thing that people like about ketogenic diets is that, as long as you strictly restrict your carb intake, you can eat as much as you want! If all of this sounds familiar it's because most of us first learned about ketosis when the Atkin's diet became popular back in the 70s. Unlike the traditional Atkin’s style low-carb diet, which was pretty high in protein, today’s ketogenic diets tend to be much higher in fat, up to 80% of calories.
You will probably lose weight on a ketogenic diet, despite being able to eat as much as you want. Contrary to what you read online, however, very little of this has to do with the metabolic "magic" of ketosis. Converting fat into ketones and protein into glucose does burn up a little more energy than burning carbs for fuel. But this ends up being a very small factor. The main reason that people lose weight on ketogenic diets is that they simply take in fewer calories.
Being in ketosis has a rather profound appetite-suppressing effect. Anything that suppresses your appetite is obviously going to make it easier to limit your calorie intake. Another reason that people take in fewer calories is that a very high fat diet—as fun as that might sound—is not necessarily very appetizing.
Weight loss on a ketogenic diet is likely to be fairly rapid, especially at first. But much of that initial weight loss is water. Being in ketosis is very dehydrating and can even lead to electrolyte imbalance. (This is why this diet used to only be done under medical supervision.)
Although a ketogenic diet does force your body to burn fat for fuel, research finds that this does not translate into losing more body fat. In studies that have compared the ketogenic diet to other diets, total weight loss and fat loss was not significantly different. In some studies, lean tissue loss was greater on ketogenic diets than on other diets. If you are on a ketogenic diet, you can mitigate some of the muscle loss with strength training. (And for tips on that, check out the Get Fit Guy podcast.)
The truth is that rapid weight loss sets the stage for weight regain, by increasing lean muscle loss and decreasing your metabolic rate. That’s why I am always making the case for slow weight loss.
Most of the research on ketogenic diets and its effects on diabetes or heart disease risks has been done on rats. And, for rats, anyway, the ketogenic diet isn’t looking so good. It tends to increase bad cholesterol and triglycerides and reduce good cholesterol. It also increases insulin resistance and diabetes risk.
Things seem to go a bit better for the humans than they do for rats. For type 2 diabetics, the ketogenic diet appears to have positive effects on blood sugar metabolism, but unfortunately, these appear to be temporary.
The ketogenic diet also tends to have positive effects on cardiovascular risk factors such as triglyceride and cholesterol levels in humans, but this may be mostly due to weight loss and not specifically the ketogenic diet. Unfortunately, we’re lacking data on the long-term effects of ketogenic diets on heart disease and diabetes risk.
If you are doing a high-fat ketogenic diet, research suggests that emphasizing unsaturated fats like olive oil, nuts, and avocados and not overdoing it with saturated fats such as coconut oil and butter may offer your heart some protection and lower your diabetes risk.
The truth is, we don’t have much data on the long-term sustainability of the ketogenic diets in humans, but longer-term studies in rats are not encouraging. Rats put on a ketogenic diet tend to lose weight initially but after a few months, weight loss slows—which wouldn’t be so bad, if they stabilized at a lower weight. But instead, they start regaining and ultimately end up heavier than when they started.
We don’t know whether it might work the same in humans. The "long-term" human studies we have max out at about 24 weeks, which is right about the time that the rats started regaining their weight.
But perhaps the more important question is the issue of whether you can make this very restrictive regimen a permanent lifestyle. And here’s the thing: You can eat 80% Paleo or 80% unprocessed, but there’s no such thing as an 80% ketogenic diet.
You have to be on a very low-carb diet for about three days in order to get your body into a state of ketosis—and a single carb-rich meal will put you back at the starting line. Without the appetite-suppressing effect of being in ketosis, continuing to eat a lot of high-fat foods could lead to taking in far too many calories.
If you get tired of the ketogenic lifestyle or menu, you are going to need to find a new strategy for managing your appetite and your calorie intake. Otherwise you are likely to regain what you have lost. And losing weight and then regaining it may be more harmful to your health than not losing weight at all.
The other thing that concerns me about long-term use of this diet is that very low-carb diets are likely to be deficient in fiber, folate, vitamin C, calcium, and vitamin D. If you are committed to this as a long-term adventure, be sure that you have those bases covered.
Do the pros of the ketogenic diet outweigh the cons? For me, they don’t. Whatever you are doing to lose weight needs to be something you can sustain long-term. I’d also rather see you lose weight more slowly, because this helps preserve your metabolism and lean muscle mass.
Unfortunately, a lot of people are still in the market for fast weight loss by whatever means necessary. I’m sure my verdict isn’t going to put much of a dent in the keto frenzy. But if you’ve been wondering whether you should jump on the keto bandwagon, I hope this overview of the pros and cons will be helpful.