My son is struggling with this right now and it's entirely my fault.

I've never been outside of 15 pounds what I weighed in High School and I was underweight in High School. As a man in his 40s, I'm in better shape than I was back then, lower body fat, slightly more muscle, triglycerides/LDL/HDL better[0].

I eat how a 10-year-old kid would eat if he didn't have parents. All of my breakfast foods (which I never eat in the morning) have cartoon characters on the box. Fruity/Cocoa Pebbles, Honeycomb, Cookie Crisp, Lucky Charms, Cocoa Krispies, Fruit Loops, Frosted Gluten-Wheats, (of course) Cap'n Crunch ... actually, worse -- I buy the Malt-O-Meal generic versions of each that come in the cement bags.

I can't think of the last time I drank water. I drink Coca-cola, instead. At least twice a week I make a half-gallon chocolate malt and consume the entire thing. Sometimes that's dinner. It's the only reason I own a blender. It's the reason blenders last about 2 years, tops, for me -- typically with dead motors or a shattered carafe[1]. I make the whole carafe for myself (the kids split half of one). I rarely eat Breakfast or Lunch. Dinner is something frozen and tossed in an Air Fryer or ordered. I often add a meal just before bed that consists of several bowls of one of the previously mentioned cereals.

I do none of this with any sort of planning. I get hungry, I find food, I eat it. If I'm depressed, I don't eat. If I'm busy doing something else I might forget to eat. When I'd travel solo for work, I'd go through my receipts and find out I ate twice at the airport on the way out/in, and spend an hour looking for meal receipts until I figure out that -- yes, I actually did only pay for three meals that week. Yes, one of those "meals" was an Arizona Peach Tea, half of which was left somewhere and for some reason I felt it necessary to both get and keep the receipt for the $1.00 purchase but at least the expense department will be satisfied ... if not a little surprised.

My 16-year-old son is having success with a restrictive Low Carb/No Sugar diet and I've found myself at a loss as to how to help him, but many of the things the author mentioned (short of a vacation I can't afford) have worked very well.

My observation is that the author's top two items are the most effective parts if you can do the first.

My alternative to the "vacation" for him is distraction. He's a lot like me: an indoor cat who likes computers and video games and doesn't like sports. I focused on things he really liked that were active and upgraded him -- he got a better VR kit and we upgraded the OneWheel[2]. He learned the first few days that when he gets hungry, the best thing to do is use one of those and the one that gets him out of the house is the one that works best. Though we could have taken a vacation for the cost of the upgrade, he wouldn't be putting in ten miles on it every day.

And I think that's part of it: finding something he loves to do which involves a lot of exercise. So far, that's the OneWheel GT (and I feel the same way). He uses the VR. It's about what you'd expect. The few games he enjoys aren't much exercise and the ones that are exercise focused aren't any fun. Luckily he doesn't get motion sick, but that was a pointless purchase for these purposes. And I assumed it would be: I've been through all of the previous attempts to make exercise fun with video games: Wii, every version of Kinect, various others dating back to the Nintendo floor pad with their weird Olympics game, both of which I destroyed in my youth. They usually make some form of exercise less effective while making "wanting to do that form of exercise" slightly more attractive for a brief period of time.

The optimal situation would be a game that can be played at home with low-cost equipment which "people want to play because it's fun to play" that happens to require a reasonable amount of physical exercise to use. Ideally, it'd be something that wouldn't be "more enjoyable with a more common control scheme", nor would physical strength greatly improve ones ability to master the game (so, like most video games, they're more mental strategy vs precision muscle memory) and would be multi-player. I've yet to encounter something that doesn't fall over on all of these points so badly as to make it worse than traditional exercise.

[0] I was a kid during a brief period when they advocated giving children as young as 10-years old cholesterol tests and then putting them on low-fat diets when they (generally) had "High Cholesterol".

[1] Which is only a problem if the carafe is for an ALDI Aisle of Shame $39 blender and finding a replacement is either impossible or almost as expensive. After every expensive blender I owned failed, I'd somehow end up finding a crappy one at ALDI figuring "The $200 one died quickly, might as well save the money this time."

[2] We had a Pint and we've gone through a few tires and about 9K miles on that one. When ridden hard, you come home soaked head to toe in sweat, but it's one thing that he enjoys as much as (if not more) than playing video games.