New thinking claims that you can lose the weight you’ve always wanted to by fueling your metabolism and burning fat by eating fat. Yes, you read that right. Learn what nutritional ketogenic eating is and what butter and bacon have to do with (your) weight loss.
Photo credit: Brent Hofacker/ iStock/360/ Getty Images

Your body runs on fuel. The question is where should this fuel come from? Healthy eaters have traditionally aimed for a balanced diet of carbs, protein and fat. In the 1990s, fat-free food became the coveted secret to weight loss, but today some people are not only welcoming fat back into their homes and onto their plates, but are replacing carbs and protein with it. This is called nutritional ketogenic eating and it might be the secret to feeling full and losing weight, by eating fat.

Welcome home, butter

The premise of nutritional ketogenic eating is teaching your body to run on the fat you eat and the fat you store. Here's how it works. When people eat fewer carbs, their bodies turn to fat for energy. The basis of putting your body into a state of ketosis is flipping the switch from your body running on the carbs and sugar you eat to running on our own body fat. Once this switch is made, you say goodbye to bread and pasta but hello to high-fat, filling foods such as avocado, beef, cream and butter. We were raised on a "food pyramid" that taught us that half of our plates should be filled with carbs, a quarter with protein and a quarter with fat. Changing up this balance has been the basis of many diets, usually by trading carbs for protein, but the classic nutritional ketogenic diet consists of a 4:1 ratio by weight of fat to combined protein and carbohydrate.

The science behind ketosis

The trick with reaching optimal ketosis is to not only decrease your carb intake, but to also decrease your protein intake.

Ketosis is a state in which the body has an extremely high fat-burning rate. Even the brain runs on fat, via ketone bodies. These are energy molecules in the blood — like blood sugar — which become fuel for our brains after being converted from fat by the liver. The trick with reaching optimal ketosis is to not only decrease your carb intake, but to also decrease your protein intake. And the secret to that is to fill your diet with more fat.

If the diet is changed from one that is high in carbs to one that doesn't have enough carbs to replenish glycogen stores, the body goes through a set of stages to enter ketosis. During the initial stages of this process, blood glucose levels are maintained through gluconeogenesis, and the adult brain doesn't burn ketones. But the brain does make immediate use of ketones for lipid synthesis. After about 48 hours of this process, the brain starts burning ketones in order to more directly use the energy from the fat stores that are being depended upon, and to reserve the glucose only for its absolute needs, avoiding the depletion of the body's protein store in the muscles.

In the past, ketosis has been deliberately induced by use of a ketogenic diet as a medical intervention in cases of intractable epilepsy. Stephen S. Phinney and James S. Volek coined the phrase nutritional ketosis for those using ketosis as a means of weight loss.

Does it work?

Those who have tried to lose weight via a nutritional ketogenic diet have found great success as long as they've done one thing: understand how it works. There's a science to nutritional ketogenic eating and it needs to be understood so you not only know what's going on with your own body but also so you're not making food switches that sabotage your other choices. Each part of nutritional ketogenic eating is interconnected, so if you're eating in this way to lose weight, you can't for example eat high fat and high protein or high carb at the same time. Peter Attia, M.D., nutritional researcher and co-founder and president of the Nutrition Science Initiative (NuSI), blogs about this topic thoroughly and says that in a word, yes, this works — for some people and when done correctly. So you have to understand the hows and whys behind this kind of eating and make it a long-term change rather than a short-term diet. His series on this topic is an excellent nutritional ketosis primer and Robert K. Cooper's Flip the Switch also touches on how and why this kind of eating may be one of 12 switches you can flip to create fat loss.

Each part of nutritional ketogenic eating is interconnected, so if you're eating in this way to lose weight, you can't for example eat high fat and high protein or high carb at the same time.

Nutritional ketosis, in the hot seat

Not everyone is a nutritional ketosis fan. Melissa Burton, RD, CDE is a registered dietitian and certified diabetes educator who focuses on women’s health. She holds a certification in the Training in Adult Weight Management from the Commission on Dietetic Registration and blogs about food, fitness, family and Duran Duran at The Valentine RD.

Burton explains her personal and professional thoughts on a nutritional ketogenic diet starting with, "I'm not a fan," and going on to explain the whys behind her thinking.

Burton says, "Personally, I’m not a fan of diets of any kind and I view the popularity of the Ketogenic Diet (20g - 100g of carbohydrates per day) as the extreme version of the Low Carb (<130g carbohydrates per day which is the RDA - Recommended Daily Allowance for carbohydrates) movement as a weight loss method. The Ketogenic Diet is usually a medically supervised diet used as a form of treatment to reduce the occurrence of seizures in people with epilepsy (due to the high level of ketones produced in the body from utilizing fat instead of carbohydrate as a source of energy). The human body is designed to use carbohydrates as its primary source of energy and unless there is a medical condition (such as epilepsy or diabetes) that requires limited carbohydrate intake, I don’t support any intake pattern that advocates changing what the body requires to obtain optimal operation — especially if the primary purpose is for weight loss purposes."

Burton is not alone in her thinking. Many nutritionists have downplayed the long-term benefits of dieting in this way. The kicker, is that nutritional ketogenic advocates like Attia actually agree advocating for a lifelong eating change and thorough research before diving into this way of eating. And that's something we do love about nutritional ketogenic eating — its push for thoughtful decision making about the fuel we choose to run our bodies on.

While Burton says that the nutritional ketogenic diet isn't something she’d recommend for short- or long-term weight loss or maintenance, she — like Attia — does say this: "I’d recommend examining patterns of intake and noticing if a... [change] could be warranted."

Share with us!^ What do you think about the nutritional ketogenic diet? Is it something you want to learn more about? Would you try it? Leave us a comment below!

More on new ideas on healthy living

Alternatives to vegetable oil
A healthy must-have: Apple cider vinegar
The skinny on artificial sweeteners