The Atkins 20 diet has been proven to be an effective weight loss diet and has helped some people control Type 2 diabetes. The Atkins 40 is very similar to the Atkins 20, but it’s not as strict. This is a low-carb diet that is designed for people who have less than 40 pounds to lose. Participants are allowed 40 grams of carbs a day. This diet encourages lots of veggies, as well as portion control, along with nutrient-dense carbs. This diet is backed by valid research.