Before You Try the Ketogenic Diet, Read This

Louison Labeaume believes a ketogenic diet has done him a lot of good. Not only has he lost 25 pounds on the popular low carb/high fat regimen, he even wonders if it helped push his prostate cancer into remission.

While some research has been conducted into the diet’s ability to starve cancer cells, there has been little evidence to date that this could be the case.

“I’m not going to say that the diet did it. I don’t know what did it,” says Labeaume, a database administrator for Alameda County. “But it was very stunning.”

Labeaume is not alone in his avid fandom of the ketogenic diet, which is designed to coax the body into burning fat instead of glucose. The diet is everywhere these days, endorsed by bodybuilders, biohackers and patients suffering from an assortment of ailments, including epilepsy and diabetes. A search on the term returns well over 1 million results.

Ketogenic diets run counter to the traditional dietary recommendation of limited fat intake. Can they really help you lose weight? And are they safe?

I asked four experts to weigh in:

• Dr. Larry Cheskin, director of the Johns Hopkins Weight Management Center in its school of public health
• Amy Reisenberg, a registered dietitian in the Stanford Health Care network
• Norae Ferrara, a registered dietitian at the San Francisco Nutrition Clinic, which provides personalized nutrition therapy
• Dr. Marcelo Campos, a lecturer at Harvard Medical School and clinical assistant professor at Tufts University. Campos is also a doctor of internal medicine who has seen dozens of patients on the diet and has written about it.

What Exactly Is the Ketogenic Diet?

When the body is starved of carbohydrates, stored fat is broken down into fatty acids and metabolized into molecules called ketone bodies, which are then used by the body for fuel. This process is called ketosis. Weight loss occurs from the depletion of fat stores.

A diet that induces ketosis calls for approximately 60 to 70 percent of daily calories from fat, and the remaining 30 to 40 percent from carbohydrates and protein -- different diets call for different ratios.  A standard daily serving of carbohydrates on the diet ranges from 20 to 30 grams, which equates roughly to one banana or two slices of bread. For comparison, the World Health Organization's dietary recommendations allow for as much as 50 grams of different types of sugar alone, and state that fat make up no more than 30 percent of a person’s daily calories. 

Ferrara, the San Francisco dietitian, emphasizes that the ketogenic diet is not high-protein, like the famous Atkins diet; she says protein is also processed in the body as glucose, and too much of it can kick the body out of ketosis. 

However, Cheskin, of Johns Hopkins, while concerned over the high fat content of many ketogenic diets, says low carbohydrate intake is the only important consideration for inducing ketosis. 

Labeaume, the guy who has lost 25 pounds on the diet, says, “I started by eating tons of bacon like everybody, but eventually you take a step back from that.” Now he eats mostly green vegetables and gets his fats from butter, coconut oil, cheese and nuts, plus a little bit of meat.

Who Will Benefit?

The dietitians and doctors I talked to all think the diet can be beneficial and effective for those patients who have a lot of weight to lose or suffer from Type 2 diabetes and need to control their blood sugar.

“I think it's a good diet to jumpstart weight loss, more than some of the other popular diets I've seen,” Reisenberg, the dietitian for the Stanford Health Care network, says.

Studies in mice suggest that ketosis can increase lifespan, enhance cognition and prevent tumor growth, and followers of the diet anecdotally report mental clarity, alertness and sustained energy,

But long-term research on the diet in humans is scarce, and Reisenberg and Cheskin think it's primarily the lost weight and not ketosis itself that drives any health improvements.

“It is always true that when you go on a strict diet, your health numbers almost immediately start looking better, and it doesn't matter if it's a ketogenic diet or just cutting calories,” he says.

What Are the risks?

For the most part, the experts said the diet is safe for healthy people. However, all four talked about a risk of vitamin and mineral deficiencies. Constipation is also a common side effect.

“The primary advantage of a ketogenic diet is that it basically enables you to comply with a low-calorie diet better,” says Cheskin. “The benefit is primarily from the perspective of what it feels like to be on a diet, that you are generally less hungry for a different calorie level.”

Additionally, a diet with a lot of bacon, cheese, cream and butter can -- surprise, surprise -- take a toll on your cholesterol. Followers of the diet often initially see a spike in LDL; that’s the “bad” kind of cholesterol, linked to cardiovascular disease.

Campos, the internist, says he’s seen some patients’ cholesterol initially go up, then drop to pre-diet levels after 6 months, potentially due to lower insulin levels, he speculates.

However, Reisenberg, who specializes in working with cardiology patients, says that many of the people she sees come to her precisely because they are experiencing dangerously high cholesterol levels after years on a ketogenic diet.

Cheskin agrees. “The long-term health consequences of a high fat — especially a high saturated fat— diet is still generally believed to be not good for you … which is why I encourage people to make it moderate-to-low fat as well as low-carbohydrate."

Campos and Ferrara say the bigger risk may come from frequently starting and stopping the diet. “People who go into those yo‐yo diets, they tend to have increased cardiovascular risk,” Campos says.

One study found that people who went into ketosis for just one day had a higher blood sugar level than when they began the diet.

There’s other research that indicates flitting up and down the weight scale can be bad for your health. Cheskin, however, thinks it's even worse to simply remain overweight.

“To stay at a steady heavy weight is more dangerous,” he said, than frequently dropping and adding back pounds.

So Would They Recommend it?

Three out of four of our experts say the ketogenic diet is so restrictive, they would not recommend it for healthy patients who just want to lose a little weight.

“I’m hoping it’s another fad diet,” says Reisenberg. Instead, she advises her patients to follow the Mediterranean diet. “There is so much research out there showing that following a mostly plant-based diet that's got a reasonable amount of carbohydrates [and] a little bit of lean protein, whether it's animal-based or plant-based, and then lots … of nonstarchy vegetables reduces all risk factors for all causes of mortality.”

Campos agrees but recommends the ketogenic diet for short periods of time for patients who need to make a drastic change and have not been able to meet their goals using other strategies.

Only Cheskin endorsed the ketogenic diet as relatively effective for the average person who wants to lose weight.

“There's a steady accumulation of evidence that, at least for compliance and initial weight loss, the low-carbohydrate dieting approach is better,” he says.

He added, however, that, "Long-term, no diet works very well. It's more are you going to make long-term changes that you're going to be able to stick with for the rest of your life.”

Nevertheless, research continues into the fats versus carbs debate: A recent large-scale study that tracked 135,000 people in 18 countries over 7 years found that a diet high in carbohydrates was associated with increased risk of mortality, while a high-fat diet was linked to a lower risk. “Global dietary guidelines should be reconsidered in light of these findings,” the authors said.

Still, as you probably know by now, every expert will tell you reducing food intake is just one- half of the weight-loss equation. The other half?

Quit reading about diets on the internet and get yourself some exercise.