No, this is, simply put, bull****.
If you eat fewer calories than you burn, you lose weight. More than that, we simply don't understand. The biochemistry is too complicated and has not been studied well enough.
Carbohydrates and fats are ultimately calorie sources. Your body burns them.
In the short-term, the only two things that matter for "health" are protein and calories.
In the long term, there are certain trace amounts of various vitamins you need. Past that, we simply don't know - why do you think the status quo for "healthy eating" changes so often? Human nutrition is really ****ing complicated, and we don't fully understand it.
This is about converting less of what you eat into fat on your body after you have lost weight. Meat is tasty and you eat less of it to get full than you do pasta and bread, and it's something that people can stick to, trying to stick to 'boring' meals after a diet usually doesn't last.