On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off. This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.
Basically, the effect of exercise on our weight is overrated. That’s why it’s only number 15 on this list. There are other things you may need to take care of first. It’s not a good idea to eat unhealthy processed food, drink sugar water (so-called “sports drinks”) or be on medications which can force you to exercise for hours daily just to compensate. Metaphorically that’s like digging a hole, into which you put your ladder, on which you stand and paint the basement-level windows of your house.
Just taking the stairs instead of the elevator, or getting off the bus one stop earlier, is probably not going to change the numbers on your bathroom scale. It’s a myth. Studies show that if you just start exercising, you’re likely going to need at least 30-60 minutes of workouts per day to noticeably lose weight. Part of the reason is that exercise makes people hungrier, and eating more reduces the effect on weight.
But beyond that, experts aren't convinced that the keto diet has any other scientifically-proven health benefits. In fact, it may have some distinct downsides. If you follow the keto diet incorrectly, for example (like by eating lots of saturated fats, versus healthy unsaturated fats), you're at risk of raising your cholesterol levels. “The best strategy to keep your heart healthy is to get as much fat as possible from unsaturated sources such as olive, avocado and canola oils, nuts, seeds, avocados, and olives," says Ansel.
If you want to lose weight, consider starting by avoiding sugar and starch (like bread, pasta and potatoes). This is an old idea: for 150 years or more there have been a huge number of weight-loss diets based on eating fewer carbs. What’s new is that dozens of modern scientific studies have proven that, yes, on average low carb can be the most effective way to lose weight.