I've been reading and doing research on healthy eating, nutrition, and weight loss for a number of years. I am not a nutritionist, but have learned something about these topics over the years. I wish McCandless would produce a similar visualization for claims about healthy eating.

In the meantime, here is my guideline:

Definitely Good	Unclear	Definitely Bad
Eating breakfast	Fasting	Short term diets
Eating when hungry	Whether bread is good for you or not	Crash diets
Eating slowly	Stress control -- very important for overall health, but not proven to cause weight gain or loss.	Gimmicks, typically supplements that will cause magic weight loss. Not one has every been shown to work in the long term, and many are actual scams or have caused damage.
Tracking, being very aware of, what you eat	Exercise for weight loss. The evidence seems to be leaning away from this. But undisputable is that we need regular exercise for overall health.	Depriving yourself. In the long run, you can't out will power hundreds of thousands of years of evolution. Depriving yourself is a sure way to fail.
Caloric control works for weight loss. I.e. Weight Watchers works, if you can do it.		Restriction diets fail for probably 90% of people because people feel deprived. (They work, however, for the 10% of people who don't feel deprived on the diet.)
Hormonal control works for weigtht loss. I.e. controlling carbs, mainly.		Trying to fool your stomach -- e.g. by drinking water.
Long term dietary changes work. Changing the way you eat, for the rest of your life.
Fat is needed in your diet.
Restriction diets, such as the Paleo Diet, or the Weight Watchers "Simply Filling" Diet, work, if you can stay on them for the rest of your life.
Bariatric Surgery works.
Learning to be truly concious of when you are full works.
Getting enough sleep is huge.