Greater awareness of health issues and how to gain and maintain a healthy, smoothly-working body are good things. The diet industry is not really after that. The diet industry is focused on selling people on the idea that they should be dissatisfied with their bodies as they are, and the idea that only (their specific) $PRODUCT_OR_SERVICE can effectively change the cause of the dissatisfaction.
One of the many toxic things about the diet industry that I very much dislike is their collective addiction to drastic measures. You should immediately begin walking a mile a day or having epic workouts. You should immediately drop eating whatever you were eating and start eating their idea of a good thing. You should replace all your meals with their handy product and only eat according to their plan, and repent mightily if you slip, for you have so totally sinned. Some people can adjust happily to drastic measures. Some people can only do it as long as they see immediate results. Some people can try drastic measures briefly, but find it inconvenient and alien and soon find that the benefits of the regime are outweighed by the hassles.
It's those last two categories of people, of course, who the entire industry is aimed at, with new and different fad diets that they haven't tried before, new and interesting exercise types and machines. Perhaps this one will work. Perhaps I can maintain interest in that. Maybe I won't quit this time. I feel so lousy for quitting when all those people stuck with it and saw results. I'm such a loser.
If you're not a person who reacts well to drastic changes in anything, why the fuck are you trying to do that with food and exercise in the first place? Trying to do things against your own nature leaves you fighting yourself, and devoting more energy trying to leap over walls when you could be quietly edging around them. Of course I can't maintain a habit of working out violently for half an hour a day for more than a few days when I'm not used to doing it. Of course after five days of sticking to a draconian diet plan I get hungry and commit what would be reckoned at five mortal sins by eating something I've been dying for. I'm not psychologically set up to handle that sort of thing. I'm a fucking procrastinator, and I take the path of least resistance. Why the hell is the diet industry glaring at me? Because they're trying to play off that and guilt trip me, and I have fucking had it with their bullshit, because what I can discern of their tactics by seeing ads only serve to make me even more fucking pissed off. They are trying to convince me to hate myself because their plan which is not formulated for someone of my psychset is not working? I don't fucking think so.
The only reason I'm working out right now and losing weight is because I was able to trick myself into thinking that I could actually continue doing what I was doing without making any major rearrangements of what I was doing and still get in a little bit of exercise. A recent study showed that instead of it taking an hour of exercise a day to maintain weight, it only took half an hour. "Hell," I thought. "I spend half an hour a day on housework." So I decided that I could make sure I spent at least half an hour a day in motion. And I just started timing it. I realized that I was spending about 20 to 25 minutes a day moving. "I can tweak that up," I thought, and started timing when I walked. Timing it led to poking it up just a little more every day. I was shocked when I started noticing that I was getting less tired, having more energy, and even wanted to walk extra. This happened over a period of several months, hardly overnight. At the beginning, I tried setting half an hour aside to just boogey righteously. That didn't work so well. That was disruptive to my knees and my schedule, and I quit it. I kept walking, though, because I didn't have much choice in that, since I don't have a car.
Some people can change lifestyles effortlessly, or make it look effortless, or worse, make it look like you can make a drastic change just by deciding to, and imply that if they did it, you can, and if you can't make that change by deciding to, you lack willpower, because, after all, they did it, even though they didn't like it. There's no place in the diet industry for lazy bastards who need to take things a little bit at a time, because the diet industry makes its money off of people who yo-yo diet, going on health binges, then stopping, then going back on another health binge -- which is one of the worst things you can do for your health. It's possible to gain 100 pounds from yo-yo dieting, people. Don't do it. If someone actually is able to make a drastic lifestyle change all at once and stick with it -- great. More power to you. But know that you are probably in the minority, and just because it worked for you, doesn't mean that it's going to work for anyone else who isn't psychologically set up to make some drastic change. If you expect someone else to make drastic change because you were able to, and use yourself as a good example, do realize that you're setting the person you're trying to help up for a serious case of self-loathing, and yourself up to be loathed by them for making them feel that way, even though you were only trying to help. That your intentions were good still doesn't change the fact that the person you were trying to help only wants you to shut up about how Noble and Righteous you are before someone gets a fist in the face.
Unfortunately, the loudness of the diet industry and their use of atypical cases with immediate results and inhuman tenacity makes it so that people who actually are doing things for themselves and doing it right, and then letting loose with some hard-earned "Yay me! I feel so great about myself!" get flak from people who are sick of the diet industry. They get accused of shoving how Noble, Righteous, and Better Than Thou they are in the faces of those who can't begin to live up to their shining example, even when they were just celebrating something they did right, and not intending to imply that anyone else should be doing the same.
People are generally apt to lash out at someone who's making them feel like hell. If the diet industry makes people feel like hell, people are going to avoid anything that smacks of "health-conscious bullshit" in self-overprotection for something that they know doesn't have their best interests at heart. This makes things worse for health-oriented education and advocacy, when people are avoiding the diet industry to protect themselves, and have gotten overly cynical of anything that resembes the latest diet industry buzzwords. If people are actively neglecting their health to give the diet industry one in the eye, it becomes a self-reinforcing cycle -- the diet industry attempts to prey on low self esteem in people neglecting their own health, making people more defensive and less likely to actually do something to improve their health before drastic measures are deemed necessary.
So, if the diet industry is going about it wrong, how does a lazy bastard start working to improve health? Just pick one little thing that you know is good for you that you don't do enough and try to do it more. Once you've got that down, pick something else. Don't expect to see any results, ever. (You may see some, but expecting to see them starts in with the "I'm not good enough at this" cycle, so just do it because you want to, not because you expect it to make visible change.) Look at nutrition information on food, if you're not, and read up on what all the various components of food do for someone's body. Figure out where you could put a five minute walk into your day. Hell, even a two minute walk. Until you can put a two minute walk into your day, don't even try for a ten minute walk, much less a half hour walk. Drink an extra glass of water. Keep a glass of water by the place where you normally like to spend time. Give someone the finger the next time they propose you make sudden drastic change that you know you'll never be able to maintain. Try to avoid feeling guilty about not having the mindset to make sudden drastic changes when those around you do make sudden drastic changes. Know that you deserve to be in decent health, and you know your body better than the diet industry at large ever will.