SPOKANE, Wash. -

The paleo diet is the hottest way to lose weight and get in shape for summer right now. And while the eating plan may be new, it dates back to our ancestors. 

The concept is simple, if the cavemen didn't eat it, then neither do you. 

The paleo diet is a high-protein, low-carb diet that's popular with celebrities and cross-fitters. 

The idea is to only eat what our pre-historic ancestors did, like meat, fish, leafy greens, vegetables and seeds. But it also means you have to say goodbye to any legumes, grains and processed foods, like pasta or candy. 

The point of the diet is to eliminate foods that are of low nutritional value and cause excess weight gain, with the hopes of making you healthier overall. 

According to doctors, the paleo diet is rich in protein, which helps keep us feeling satisfied throughout the day, so we avoid hunger pangs. Another benefit is that the diet has no processed foods, which is always good for you. And paleo-supporters say they have seen improvements in their mood and a boost in energy. 

But doctors say there are some downsides to the diet. 

Doctors say the biggest problem is the diet eliminates other healthy foods like whole grains. They also  say you eat more daily protein and fat than is recommended. Another drawback is the diet is hard to maintain. Going paleo requires a lot of work and is very expensive. 

Doctors say the paleo diet can be a great way to kickstart your weight loss, but anyone considering doing the diet should supplement their diet with a calcium and Vitamin-D supplement.