First, there was the anti-fat movement. Everyone ran from fat like it was the plague, believing it to be responsible for heart disease and obesity. Turns out, neither is true, quite the opposite in fact, and fat is generally good for you (excepting, e.g. trans fat). What happened, though, was that fat was replaced by sugar in our diets. Leading to obesity, diabetes, and heart disease...
Alongside the anti-fat movement came olestra, the fat substitute that solved the problem that people created with the fat witchhunt. This was their fat savior, and what was the general response? Everyone was afraid of this scary chemical, worried that it would cause anal leakage (hint: it doesn't); they burned it alive and went about their merry lives with a jug of soda in their hands.
So, now we're knee deep in the consequences of that previous diet, and people say they want to be healthy again. Science creates artificial sweeteners, so as to sate the new desire for sugary food and drink. The response is again one of unfounded and irrational fear.
So people turn to what they view as their last bastion of hope: vegetables. But no, we couldn't just eat vegetables. We could only eat them if they were organic. The general thinking being that organic vegetables must be healthier, and avoid dangerous, scary pesticides (hint: the pesticides on organic food are worse). Problem is, vegetables were expensive and difficult to use in the first place (they spoil quickly, requiring frequent market trips). Organics only made it worse, for both organic and non-organic sources. And to top it off, people are wailing against GMO, which would have presented a solution to the insane desire for "organic" foodstuff.
I just don't get it. The average person bemoans their health and cries for a better diet, but every step they take is towards something worse. A great example I've found is bacon. I tell people that bacon is good for them; a healthy choice. Every time I receive puzzled looks and they think I'm joking. Usually while they stuff their faces with hamburgers. But guess what? That hamburger comes with a calorie loaded, glucose spiking bun, and sugary sauce. The beef it's made from has perhaps the worst impact on the global environment of any animal based food. And people will scarf down their entire 1000+ calorie burger, only to feel hungry enough to eat some fries to top it off. My bacon? It's a measly 43 calories per slice, with me maxing out at 4 slices on my best days. I feel full and sated afterwards, with none of that hamburger bloat. Pork is significantly better for the environment compared to beef. And I didn't have to put sugary sauce or carb heavy buns on my meal. And all that fat? Bacon has the same fat content as a hamburger.