This is about sugar alcohols, not simple sugars, and total sugar consumption in the US has been declining since a peak around the turn of the millennium, reverting back to levels on par with the 1970s, yet overweight/obesity rates just kept right on climbing until the recent advent of GLP-1 drugs.
If your calorie intake is higher than your calorie usage, it doesn't matter how little sugar you take. People ingest more calories than ever (relative to their calorie usage) and barely engage in physical activities (relative to their calorie intake). Sure, other factors might worsen this but doesn't change the underlying core
Most nutritionists would today argue that is far too simple a model. Your body does not metabolize all calories in the same way. The role of your microbiome in terms of metabolization was barely understood at all only 50 years ago, and we're only now starting to get a handle on it.
If it were a case of "calories in, calories out", all the experiments down by food technicians to understand what is happening in the brain when you consume certain flavors (they were literally getting people to taste soda in an MRI scanner decades ago), would not be an efficient use of time and the food industry would collapse.
If you eat 2000 kCals of lettuce, your body is going to do very, very different things to eating 2000 kCals of potato fries, including how it stores or consumes energy in that moment. Importantly, what your body does is likely going to be very different to what my body does. 10% of the population can stay slim while over-eating crap, because they are genetically lucky. A %age of the population will struggle to stay at a healthy BMI even if they eat mostly salads and fruits.
This isn't radical new age voodoo: the best science available today tells us the calories in/out model isn't anywhere near nuanced enough to help educate people on eating healthily and managing their weight.
Tim Spector has written some material on this, and I've been reading Camilla Stokholm's book recently. It's all quite interesting, and very different to what I was taught when growing up.
I'd also do some digging on ultra-processed foods - it might stop you thinking overweight people are just doing it to themselves. They're not.
Everywhere I look around myself I see the same thing: people move very little (compared to our ancestors) and they eat often, and they eat a LOT (compared to our ancestors, of course). Sure, eating processed crap influences this in a negative way, but I think parent poster is on the point: eating in moderation and exercising more is the way...
You are going on tangents (food effects on brain, microbiome, genetics). I would be very surprised if you could find a significant amount of people for whom "Eat less, move more" would not result in lower body fat over time. The fact that some people won the generic lottery and can afford to eat more and move less does not change the fact that "Eat less, move more" works for the vast majority of the population.
> If you eat 2000 kCals of lettuce, your body is going to do very, very different things to eating 2000 kCals of potato fries, including how it stores or consumes energy in that moment.
I don't really think so. The only meaningful difference regarding the content of macronutrients is right at the start: you would have to eat about 20kg of lettuce to get there, which would overload your digestive system several times over.
If you hypothetically somehow managed to bypass this small issue, the main difference would be low fat content of lettuce compared to the fries. Bud the body can adapt to that.
It doesn't have to. Increase your exercise relative to your caloric intake, and reduced your caloric intake to the minimum needed given your increased exercise. Increase exercise intensity gradually. Do this 5 days a week for a year and I will give $500 if you don't lose several stones after that period of time.
Often, when people bring up this simple fact, lots of folks try to put excuses and variations of "it's not that simple", when actually yes it is.
