I've lost and kept off about half my bodyweight, so I feel entitled to the opinion that that's horseshit dreamed up by marketing to tell people what they want to hear. There is one definitive way to lose weight, time tested and provably infallible: consume fewer calories than you expend.

Now certainly there are some factors involved in both sides of that equation that can be adjusted by what you eat, but take it from a food addict that weight loss is most definitely more about how much you eat.