In a recent study in the Journal of Sports Medicine and Physical Fitness, Weiss and his colleagues found that participants performed worse on high-intensity cycling and running tasks after four days on a ketogenic diet, compared to those who’d spent four days on a high-carb diet. Weiss says that the body is in a more acidic state when it’s in ketosis, which may limit its ability to perform at peak levels.
And although in the short term, ketogenic diets seem safe for healthy people, we also lack long-term data on the diet, so it’s hard to confirm long-term safety with certainty. Complications seen with kids maintaining a ketogenic diet for epilepsy, for example, included kidney stones, constipation, gastrointestinal issues, pancreatitis, and vitamin D and calcium deficiencies.
The ketogenic diet is based on the principle that by depleting the body of carbohydrates, which are its primary source of energy, you can force the body to burn fat for fuel, thereby maximizing weight loss. When you consume foods that contain carbohydrates, the body converts those carbohydrates into glucose, or blood sugar, which it then uses for energy. (1)
There are so many tricks, shortcuts, and gimmicks out there on achieving optimal ketosis – I’d suggest you don’t bother with any of that. Optimal ketosis can be accomplished through dietary nutrition alone (aka just eating food). You shouldn’t need a magic pill to do it. Just stay strict, remain vigilant, and be focused on recording what you eat (to make sure your carb and protein intake are correct).
Leftovers will be another thing we will take into consideration. Not only is it easier on you, but why put yourself through the hassle to cook the same food more than once? Breakfast is something I normally do leftover style, where I don’t have to worry about it in the morning and I certainly don’t have to stress about it. Grab some food out the fridge, pre-made for me, and head out the door. It doesn’t get much easier than that, does it?
In terms of weight loss, you may be interested in trying the ketogenic diet because you’ve heard that it can make a big impact right away. And that’s true. “Ketogenic diets will cause you to lose weight within the first week,” says Mattinson. She explains that your body will first use up all of its glycogen stores (the storage form of carbohydrate). With depleted glycogen, you’ll drop water weight. While it can be motivating to see the number on the scale go down (often dramatically), do keep in mind that most of this is water loss initially.