Initial weight loss might not stick
The keto diet is notorious for delivering a quick initial slim down. That’s because carbs hold on to more water than protein or fat, says Becky Kerkenbush, R.D., a clinical dietitian at Watertown Regional Medical Center. So when you stop eating them, all that extra H2O gets released through urination. As a result, the scale might read a few pounds lower, and you may look a bit leaner.
That first drop might be mostly water weight. But research suggests that the keto diet is good for fat loss, too. An Italian study of nearly 20,000 obese adults found that participants who ate keto lost around 12 pounds in 25 days. However, there aren’t many studies looking at whether the pounds will stay off long-term, researchers note. Most people find it tough to stick with such a strict eating plan, and if you veer off your diet, the pounds can easily pile back on.
You could become constipated
Constipation is a common side effect of low-carb eating plans, including the ketogenic diet. Severely curbing your carb intake means saying goodbye to high-fiber foods like whole grains, beans, and a large proportion of fruits and vegetables, says Ginger Hultin, M.S., R.D.N., Seattle-based nutritionist and spokesperson for the Academy of Nutrition and Dietetics.
Combine that with the fact that your body is excreting more water, and you have a potential recipe for clogged pipes. You can keep things moving by getting some fiber from keto-friendly foods like avocado, nuts, and limited portions of non-starchy vegetables and berries, says David Nico, Ph.D., author of Diet Diagnosis. Upping your water intake helps, too.