Lately there has been a lot of talk about a new super kid on the block in the weight loss neighborhood. Everywhere I go, when the topic of weight loss comes up, people start talking about the keto diet and how they have heard that it literally melts fat off of you. Everybody has a friend who's cousin's sister did it and lost a 150 pounds eating bacon and eggs and they are chomping at the bit to give it a shot. And while, like any diet done correctly, you can lose weight using the keto diet, it probably isn't the right way for you to lose weight for a lot of reasons. I am here as a weight loss physician to be the voice of reason and help sort out the hope from the hype and present to you the truth in the ever-confusing world of weight loss. So let's dig in...
Yes the though of feasting on bacon and losing weight is every person's dream. But like everything, if it sounds to good to be true, it is. First lets talk about what exactly the keto diet is in order to clear up any rumors or misconceptions. The primary fuel source for your body is called glucose, which is a breakdown end product of carbohydrates and in some cases proteins. It is the gasoline that keeps the whole machine running. Now, because of how evolutionarily capable of survival as the human organism is, we don't only have to rely soley on glucose as a source of energy, and can make a secondary type of fuel from fats, the now-popular ketones, through a process called "ketogenesis". Ketogenesis keeps our engine when the carbs and proteins are in low supply.
Generally this is our body's reaction to famine, a survival mechanism developed so that we can burn our stored fat for energy when there is no food around, because your body cannot store large amounts of glucose. But you can also get there simply by switching around your carb/fat/protein intake to a ratio of very low carbs, low protein, and high fat, which is called the keto diet.
Now, like I said, eating this way can certainly help you burn off your body's fat stores and can improve a lot of other health markers, but for weight loss it probably isn't the right choice for most people for a lot of reasons, but mainly because it is just too hard to stick to. The number one indicator for a successful weight loss program for long-term weight loss is the ability of participants to stick to it. The keto diet is just too restrictive and requires too much effort for the majority of people to stay with it long-term. Let me explain that as well.
The classic keto diet calls for a ratio of 70% fat, 25% protein, and only 5% carbs as a whole for your daily calorie intake. You are going to be eating a lot of fatty foods that aren't really easily available anywhere outside of your own kitchen. Unless you are happy being a social pariah, you are going to miss out on being able to go out and share a meal with people that you want to spend time with. You will also spend an incredible amount of time prepping your keto meals to take with you to work or any other place that you plan on going outside of your home. That leads to social isolation which leads to an overall negative emotion and perception about your diet which causes people to fall off the diet over time. Nobody wants to be bummed about their efforts and people don't like eating alone, i.e. high school cafeteria.
Another reason that people fail on the keto diet is that while they may be in ketosis, they are still taking in too many calories to lose weight. Yes being in ketosis helps target body fat as fuel, but weight loss is still about achieving a negative calorie balance, i.e. using more calories in a day than you eat. It is very easy to take in more calories on a keto diet if you aren't very scrupulous with the whole process because fats carry 9 calories per gram where carbs and protein carry only 4. if you are storing fat faster than you are burning it because you are taking in more than you need then you can't very well lose any weight can you? You still have to keep your calories low.
Besides that, it is really hard to get into and stay in ketosis. Most people will tell you it takes anywhere from 2-10 days or longer of strict keto eating for your body to get there, depending on the person because each person's metabolism is a bit different. That means no cheating, not even one little slip, and once you are there, you can't slip up either. And let me tell you, slipping up is easy because the carb requirements are so low. General recommendations are 20-50g carbs per day but it depends on how the person's metabolism uniquely functions. 20 grams of carbs is extremely low and even then some people can't make it.
And the slip up on a keto diet is so much more dire than any other diet because the slip sabotages the whole process, not like a calorie restricted diet or any other diet where a slip just means you took in a few more calories. You will be kicked out of ketosis completely and have to work to get back in. You just don't have the room for error that you do with other diets, so you can't do a keto diet half-heartedly. You can't have a keto breakfast, then drink a fruit juice later and still give yourself credit for a semi-keto day because all of those extra calories that you are taking in from the high fat breakfast are all for not if you kick yourself out of ketosis!
Apart from the carbs, it seems that even eating too much protein can sabotage your ketotic efforts. As I mentioned earlier, the body can also convert protein into glucose for energy in a process called gluconeogenenis and if that is happening, no ketones for you! Most of the research on successful diets will show that a higher protein and lower carb or fat diet is really the best way to go. That is why the dietary portion of my program in my book is designed the way it is.
So to sum it all up, the keto diet isn't a lie, but it definitely isn't what it is hyped up to be. It really can help you lose weight and can improve a lot of other physiological markers that are related to metabolic diseases, but the problem is that unless you are intensely disciplined you are setting yourself up for yet another dietary disappointment. The best diet to be on for weight loss is one that you can sustain, and that is why 95% of dieters gain all the weight back plus some within 3 years. Do yourself a favor and find something easy that you can stick to.
For a sensible program that gives you the best chance for long-term, sustainable results, check out my new book "Finally you: 12 Rules for Achieving permanent Weight Loss and Lifelong Happiness". Available on my website for digital download or Amazon in paperback.
"Standard Ketogenic Diet" - 70% fat, 25% protein, 5% carbs