At the same time, many young men in the West struggle to put on weight and are underweight.

In the West? Men? I'd love to see statistics for that.

In general, being overweight is a far, far larger problem in the West, and being underweight is extremely rare outside of eating disorders like anorexia. There are people who are naturally skinny due to how their metabolism works, but they are rarely truly underweight.

For a small number of "many".

[...] according to 2010 data from the Centers for Disease Control and Prevention, these are the measurements of the average American man:

Height: 5 feet 9 inches (69.3 inches) Weight: 195.5 pounds Waist circumference: 39.7 inches

Height: 1.76 m, Weight: 88.7 kg, Waist circumference: 100.8 cm.

Depends how define many. 34.8% of men between 20-39 are obese in the US:

https://www.cdc.gov/nchs/data/databriefs/db288.pdf

That's far more a concern than whether men need to bulk up or not. Which naturally happens as men age and their metabolism slows anyway.

Depends on the country, I suppose. I'm having a hard time finding stats for US that compare underweight and overweight % of population in one study.

Anecdotal evidence from Europe: in our industry, culturally associated with obesity, I meet roughly equal amount of obese and underweight people. And I seriously doubt those underweight people spend time in the gym.

Can't decide if this is sarcastic/tongue-in-cheek or serious. If serious - would love to see source(s) for that statistic....

Serious. Don't have the statistics, but look up "gomad" for "gallon of full fat milk a day" - it is a thing for a reason.

There's a difference between weight gain strategies to build muscle and eating because you're "underweight." People not working out and eating normally will be less bulky than people who work out and eat comparatively more. But they won't be "underweight."

Everything is a "thing for a reason".

The reason could be a tiny outlier minority.

You used the term "many".

I used the term "many" specifically because I do not have the stats. Not a majority, but a significant number of people, that struggle to gain weight.

If you have no data to back up your claim you should not make that claim. The word "many" is a borderline weasel word.

Sure it's a thing for a reason... the reason is guys who are into body lifting that was an easy source of calories and protein. It has nothing to do with your narrative.

Do you have a link to any quantitative data? I'd love to see how this has changed over time.

oh yeap, been struggling with this forever.

Try some bacon.

Costco pizzas are $10 and over 4000 calories, eat one of those a day and if you don't get fat then you probably have a tapeworm in you or something. Or you're Michael Phelps during training season.

... or me at 18. Damn I miss that metabolism.

Or just have 12 stacked pancakes for breakfast at iHop + all the trimmings every day.

I don't like bacon.