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Here's the skinny on the ketogenic diet: What it is, how to follow it properly

It started with jugs of olive oil and cans of tuna, lots of it, which my husband hauled in one day and plunked on the counter.

"That's my lunch!"

That was about three months ago, and every day since there has been a new entity in our house to consider. It affects how we eat at restaurants. It does not like craft beer. It provides one more excuse to eat lots of cheese.

It is the ketogenic diet.

Heard of it? I hadn't before my husband, Phil, took up the diet at the end of March. Now I see it all over the place. Though it has been around in the medical community for decades, it seems to be taking shape as the new diet of the moment. Recipe delivery services like Green Chef are advertising new keto menu options. The other day I saw a woman walking down the street clad in a shirt that said "Keto and Slay."

It has been used as a way to treat medical conditions, most prominently children with epilepsy. But, if followed precisely, it can also lead to substantial weight loss.

The ketogenic diet is a very high-fat, very low-carb diet in which the goal is to get your body into a state of ketosis, when it begins to burn fat because it doesn't have carbohydrates to burn.

To achieve ketosis, dieters follow specific ratios of what are called macronutrients: protein, fats and carbohydrates. You will hear keto-ers talk about "my macros," because unlike some other diets, the keto diet works best if those ratios are precise. In general, that means getting about 70 percent of your calories from fat, 20 percent from protein and 10 percent from carbs.

Most people have the hardest time ditching all those carbs because the American diet is very into serving a form of potato with every meal. A general carb guideline is less than 50 grams per day, though the exact number can vary from person to person. Added sugar is out, as is fruit and some vegetables. (A medium-sized apple has about 25 grams of carbs.)

Keto can be extreme. The protein-heavy Atkins diet is a modified version of it, and the recently trendy paleo diet also shares similarities. The menu of allowed foods is heavy on meat, cheese, nuts, olives, avocados and fish.

RELATED: My husband has lost 30 pounds on the keto diet. Here's how.

RELATED: My husband has lost 30 pounds on the keto diet. Here's how.


Julie Stefanski, a registered dietitian, says the relatively limited menu and tracking macros are the toughest parts of a keto diet: Lots of people just can't stay with it, or they follow the diet incorrectly.

"One of the reasons people can't stick to it is because it's so different from the normal American diet," Stefanski says. "Normally, when you think about the average American diet, most of the foods and the calories are coming from carbs: breads, grains, cereal, anything with sugar. So switching to a really high-fat diet is a big change."

Stefanski worked at a large health system for about a decade, specifically for the epilepsy wing and a special department that treated patients with the keto diet. She got to look over the lab results of people on keto, and says it taught her a lot about how the body uses food.

The big concerns with high-fat diets tend to be: Is it bad for my heart? Will my cholesterol go up?

Stefanski says that generally, people's cholesterol levels don't change as much as you'd expect. And while there isn't a lot of long-term data on this diet, there's evidence that cardiovascular disease is caused by inflammation and that this diet can help with inflammation.

David Rohde is the founder of Largo food delivery service Paleo on the Go (, which recently started offering keto meals. Rohde started the company, which began delivering meals in 2011, with a focus on the paleo diet. Paleo aims to mimic the food groups of our pre-agriculture hunter-gatherer ancestors, emphasizing high fat and protein, plus fiber from vegetables instead of grains and no dairy.

But his initial interest wasn't weight loss. It was trying to find a diet that would alleviate symptoms of the autoimmune disorder he has, eosinophilic esophagitis.

"Living a keto or paleo lifestyle not only promotes weight loss and increases energy, but also helps to heal the microbiome of the gut and alleviate symptoms for people living with chronic diseases," Rohde says.

There is anecdotal evidence that suggests low-carb, nutrient-dense diets are better for those with autoimmune diseases like Crohn's and colitis, which are associated with excess inflammation in the body.

And though the autoimmune protocol is a particular focus of Rohde and his company, he says the new keto component was driven by customer demand.

"Keto is exploding right now, and people tend to reach for the low-quality foods. It's good for more energy and focus and all kinds of stuff," he says. "I want to help people do it the right way."

RECIPES: Three keto-friendly meals to cook at home.

RECIPES: Three keto-friendly meals to cook at home.


It is crucial to eat different kinds of fats while on keto, not just bacon, a too-simplistic mascot for high-fat diets that came about around the time of Atkins. Red meat is a minority of my husband's diet; he's a stickler for healthy fats like mono- and polyunsaturated, which are beneficial for HDL, or "good" cholesterol. A normal keto lunch for him is tuna mixed with avocado and olive oil, plus lots of snacking on various cheeses, macadamia nuts and olives.

"It should be a variety of fat in your diet," Stefanski says. "No fat is excluded, but it would be a good idea to stay away from the trans fats, the man-made ones, and that goes for everyone. We encourage people to have good sources of monounsaturated fats."

Another way people mistreat the diet: Eating all of your daily allotted carbs at once. Ideally, those macronutrient ratios should be roughly the same for every meal, with carbs spread out throughout the day. Otherwise you could throw yourself out of ketosis.

"It's not easy," Stefanski says. "I made my son mac and cheese the other day, and I noticed one serving had 53 grams of carbs in it."

But let's say you can stick to the rigid rules, like my dedicated husband has. One of the main things I wanted to know from Stefanski was whether this diet is safe, since the way it leads to weight loss involves sending the body into starvation mode.

Is it something you can continue without harmful side effects?

"When you switch from high carb to low carb, your body does produce energy in a different way," Stefanski says. "It has to burn fat. That is a natural process, but we don't use it that often. Ketosis, making ketones, is not dangerous, if you have a normal metabolism."

But Stefanski emphasizes repeatedly during our conversation that it's not a well-balanced diet. It's hard to get all of the nutrients you need from such a limited list of foods, and it's not something you should start on a whim without doing your research. (And it's probably not something you should adopt forever. My husband plans to reintroduce carbs in August.)

She recommends taking a multivitamin, plus calcium and vitamin D supplements, and getting as much food variety as possible. Also, blood tests to monitor your lipid panel and vitamin levels are a good idea every three months.

Stefanski recommends using your carb allowance on low-carb vegetables like kale, spinach, radishes, cauliflower and broccoli.

"That's going to be better for your immune system than spending that on a grain or something."

Another thing to watch out for: Don't add carbs back into your diet and still continue to eat all of that fat. That can lead to rapid weight gain.

And variety really is your best friend. Be careful about leaning too hard on some of your favorites. My husband can't even look at a wedge of Parmesan cheese anymore.

RECIPES: Three keto-friendly meals to cook at home.

RECIPES: Three keto-friendly meals to cook at home.

KETO, FIRSTHAND: My husband has lost 30 pounds on the keto diet. Here's how.

MORE COOKING: Recipes and food tips from food editor Michelle Stark on Stark from Scratch