I've skimmed the linked site. It seems to describe a way to modify eating behavior resulting in people both eating healthily and being happy about it, rather than repressing their desires for food, obsessing over diets, and suffering psychologically.
I'm not an expert on the subject; I don't know what different methods exist to achieve this kind of result and what is each method's rate of success.
My original statement that "there is no disagreement" was wrong, I should have qualified it. Some people remain healthy all their lives while just eating whatever they like. Others may be able to achieve such a state through some behavioral modification technique. Still others may remain unhappy with healthy diets. For some there may not be a healthy diet at all: for instance people suffering from obesity, which may be associated with "bad" diet, but which in some cases no dietary changes can effectively fix.
The correct statement should be that the diets formed by just eating whatever we like are often harmful, and in some of these cases no healthy diet can be found that the person likes and can adhere to without any effort.
There are fat (obese) healthy people. There's evidence that exercise is a better correlation for health than BMI or fat %.
I posted recently that "I tend to assume that things people hate are bad for them. CR may be an exception, but it's plausible that evolution would usually select for warnings that one is hurting oneself."
I think this points at an interesting question. If you know that people like a behavior, or dislike it, or love it, or hate it, does this tell you anything about whether the behavior is useful?
I expect that most people reading this question have a handy list-- one that comes quickly to mind-- of things which are good for people but that they resist. There's a tremendous amount in the culture (and perhaps more from somewhat different angles at LW) about people's reflexive preferences being wrong.
However, there's a lot where people's preferences are assumed to be in line with what's good for them that doesn't get much attention. I believe this is because there's a fascination with the drama of self-denial, but that might be a topic for a different post.
For example, people hate long commutes. I've never heard anyone say that long commutes are good for people.
People generally dislike being low on sleep.
Rather few modern people think that liking sex is a problem in itself. (Note a cultural shift-- anxiety about pleasure has been moved from sex to food.)
Nobody says that human contact is bad, even though many people like it.
And there's no cultural consensus that hating spam is bad, even though hating spam is a spontaneous response.
It's implausible that evolutionarily developed pleasure and pain should be completely out of line with well-being. On the other hand, it's a noisy signal. Should it be taken at all seriously?