Basically, if you eat less than 20 grams of carbs a day you will lose weight. If you eat less than 50 grams a day, it will be impossible to gain weight. The video touches on the science, but doesn't really delve into it. If you want some better insight check out this book.
Gary taubes is sort of a hero of mine. He will be remembered as someone that took a look around and said, "wait a minute! this is wrong!" and then set out to meticulously prove it by doing years of research on the subject.
Here is the gist of it:
One of the strangest ironies in all of dieting is that many of the problems people associate with the consumption of high fat actually is more likely to be caused by a carb-laden diet. Problems such as heart disease, obesity, diabetes, ADHD, and perhaps even cancer have all been potentially linked to originate in the Western Diet of high carb in the presence of high fat. Grains in particular have been shown to have strong links with auto-immune and inflammatory diseases like Multiple Sclerosis and Arthritis.
This quote is from the r/keto andFAQ will explain the science behind it better than I can.
I'm sure in 50 years we will look back on the whole low-fat trend and wonder how we vested interests like big agriculture, the packaged food industry, and vegetarian activist destroy our bodies.
Grains are also a huge problem, but for reasons not dependent on their carbohydrate content. Some people say grains, "are the new tobacco" for these reasons. And yeah, I'm tempted to agree although the science on gluten intolerance and anti-nutrients is very, very far from complete. Still, it's enough to make me avoid the stuff.
Now, the best part of this diet isn't the awesome food. It's that you'll feel great. After the first week I had so much energy. I don't even need my ADD meds any more. It's crazy. It's like the life hack I've been missing all my life.
Also, you don't fart on a low carb diet. So that's nice.