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Speed Keto combines keto with intermittent fasting. Here’s what experts have to say about the benefits and potential health risks of this diet. Getty Images
  • Speed Keto is a high fat diet program meant to get you into a fat-burning state called ketosis more quickly.
  • Speed Keto combines keto with intermittent fasting, when you eat only one meal a day.
  • Experts say Speed Keto is unsustainable in the long term and could be unhealthy for some people.

Keto evangelists have popularized the high fat, low carb diet as a lifestyle. But for the majority of people, the keto diet is restrictive, making it hard to maintain.

Now Speed Keto, an even more extreme form of keto, has arrived on the diet scene.

The newest twist on keto promises to tap into the body’s fat-burning system faster by integrating a controlled version of fasting.

It’s common for people to pair the keto diet with intermittent fasting, usually 16:8, which means someone only eats during an 8-hour window each day and fasts for 16 hours.

Speed Keto takes this further by advocating for one meal a day. The meal should be keto-approved, of course.

Potential weight loss is the primary selling point for a majority of the keto curious. It’s also been found to lower the risk of diabetes, heart disease, and cancer, but it may have negative health effects for other people.

We asked two nutrition experts to review Speed Keto’s protocols for benefits and dangers and answer the question: Should you try this diet?

“Speed Keto is a means of achieving faster ketosis and was created by Harlan Kilstein, who is not a medical professional or nutrition pro, but a coach,” said Cynthia Thurlow, NP, who specializes in nutrition and intermittent fasting.

The Speed Keto program is similar to the traditional keto diet in that it requires individuals to eat a high fat, low carb diet.

Similarly, it also focuses on putting the body in ketosis, a metabolic state when your body burns fat instead of glucose for energy. When your body is in ketosis, it’s basically a fat-burning machine, thus giving keto its reputation as a weight loss tool.

The difference with Speed Keto? You can only eat one meal a day. The meal should follow the traditional keto guidelines of high fat and low carb macronutrients.

“It’s main goal is to attempt to become fat-adapted faster than a more traditional ketogenic diet,” Thurlow told Healthline.

“Fasting can help speed the process of getting into ketosis,” explained Tony Castillo, MS, RDN, LDN, nutrition consultant for RSP Nutrition.

“It can typically take 2 to 4 days to enter ketosis if you have less than 50 grams of carbs per day,” he continued, pointing out that several factors, from what you eat to age and activity level, can extend the amount of time it takes to enter ketosis.

Even though you may enter fat-burning ketosis more quickly on Speed Keto, seeing a lower number on the scale might be misleading.

“Since the traditional keto and Speed Keto focus on [eating] fats, your body will excrete more water because fats do not like water. This means the weight loss you see is most likely water weight or even muscle weight, not true fat loss,” Castillo said.

While you might enter ketosis more quickly, the experts we talked to mention several downsides to Speed Keto.

“Diet programs like these are typically unsustainable and can be challenging to follow long term,” Castillo said.

Even just sticking to keto protocols when you’re dining out with friends can be challenging. With Speed Keto, dieters face the added test of only eating one meal a day.

Castillo also points out long-term effects of the keto diet, and therefore Speed Keto, are unknown.

It’s also important to review your health goals before choosing a program. For example, Speed Keto and the traditional keto diet can make it more difficult to build muscle.

It’s also likely to give you the “keto flu,” temporary flu-like symptoms caused by going into ketosis, and make you feel lethargic.

According to Thurlow, Speed Keto “is not a healthy or sustainable nutritional philosophy” and should only be considered short term, if at all.

“My concern would be that most people would get insufficient macros in during their feeding window, and that could contribute to muscle breakdown, such as catabolism or sarcopenia, and stressors to the thyroid, adrenals, or sex hormones,” Thurlow said.

“[This diet] is highly bio-individual, meaning that everyone has different factors that can make this a successful or unsuccessful strategy,” she said.

Beyond keto protocols, the one meal a day (OMAD) requirement doesn’t work for everyone.

Thurlow notes that while there are people who thrive on OMAD, “many cannot get all of their macros for an entire day in one meal, and others are way too full and uncomfortable consuming that much food in one sitting.”

In addition to the physical effects, the cycle of fasting then eating a large meal may not be good for some people’s mental health.

“When diet programs incorporate intermittent fasting, it’s important to consider past eating history, as intermittent fasting may not be ideal for someone with a history of binge eating disorder,” Castillo pointed out.

If you’ve identified that the intermittent fasting or OMAD elements of Speed Keto work well for you, know that you could apply it to a more balanced diet, too.

“Intermittent fasting can be combined with most nutrition programs with great success, not just keto,” Thurlow said.