3 people explain why they quit the keto diet: 'I felt a lot worse than I did better, even after losing weight'

• The keto - or ketogenic - diet is popular but unsustainable for many people.
• It involves eating high fat and low-carb foods, with the aim of burning body fat for fuel instead of glucose.
• Common reasons for quitting the diet include getting "keto flu," lacking energy, and being too deprived.

The keto diet is one of the most popular weight-loss strategies of the moment, despite having been ranked among the worst by the US News & World Report, where it scored particularly low for heart health and sustainability.

The keto - or ketogenic - diet requires eating high-fat and low-carb foods: about 20 to 50 grams of carbs a day. (For context, one large apple contains about 30 grams.)

To stay under this threshold, followers of the keto diet don't eat traditional carbs like bread, pasta, rice, or potatoes, but also generally avoid fruit, beans, lentils, and starchy vegetables as they are all too high in carbohydrates.

The idea is that by cutting out carbs, your body enters ketosis and burns fat for fuel, rather than glucose.

But many health and fitness experts have pointed out that weight loss that may occur while following the keto diet actually stems from being in a calorie deficit (consuming less energy than you expend) overall, which can be achieved while eating a more balanced diet including all foods.

The keto diet is not recommended for people who work out a lot because the body needs carbs for energy.

The keto diet can also lead to nutritional deficiencies when followed long term, but most people don't manage to stick to it for a long period because they enjoy eating carbs, feel too low on energy, or find they can't have a social life.

While you'll lose a significant amount of water weight when you first go keto, if a diet is unsustainable the results will be too. Which is exactly what many people have found.

Shelle tried the diet for a month but got 'keto flu'

Shelle Kearney tried keto for a month after a friend had a positive experience on the diet, but the Australian developed keto flu so she called it quits.

"Getting over the sluggish, flu-like symptoms was the hardest and I suffered with headaches a lot," Kearney said. "From what I know, sugar withdrawal headaches are common when dieting."

Kearney lost some weight during her keto month, but it wasn't worth it for how bad she felt.

"I felt a lot worse than I did better, even after dropping a few kgs," Kearney said, adding that she found it "too hard" to do keto when living a normal life and socializing.

"I actually think fad diets create a lot more anxiety within yourself," she said. "I now just make sure I make good, healthy choices and don't beat myself up every day if my target is slightly shifted."

Sarah found keto too restrictive

Keto was one of various diets Sarah Laurence tried over 15 years, none of which lasted long.

Laurence found keto unsustainable because it was overly restrictive, particularly as someone diagnosed with CFS/ME (chronic fatigue syndrome) and fibromyalgia. She struggled because there was no way to find a healthy balance and ease out of keto into a livable life.

"I'm now recovering by tracking less, weighing less, and following Jordan Syatt's "three plates three snacks" method, focusing on getting healthier and increasing activity levels slowly in line with recovery from ME symptoms," she said.

Lee didn't have enough energy while doing keto

After a month on the keto diet, Lee Chambers quit because it left him feeling tired.

"I found that being in ketosis really didn't give me the energy or clarity to keep active and doing what I needed to as a businessman and father," he told Insider.

Although Chambers lost six pounds over the month, three of those came back when he incorporated carbs back into his diet.

"I've found that fixating on a system has been counterproductive as I ended up thinking about it incessantly," he said.