I'll chime in from that group, it provides an upper bound value to work with. Since nutritional science deals with a lot of macroscopic behaviors that are just

I'll chime in from that group, it provides an upper bound value to work with. Since nutritional science deals with a lot of macroscopic behaviors that are just stupidly complex and often individually specific with lots of variance, it at least gives you some ballpark bounds to work with, assuming of course businesses are able to give accurate caloric estimates (which they often don't--even more difficult if you're eating at a local restaurant). The issue is the other side of the envelop: energy expenditure. It's quite difficult for any one person to estimate and your body will often compensate in ways you aren't quite aware of to save those precious energy calories. All you can really do is play with your caloric intake since you have some control and combine it with some information from certain exercises (use lower estimates for exercise caloric expenditures--round down every opportunity to also give reasonable upper bounds on expenditures). So all in all, a calorie is a calorie but it just provides a starting point for you to work with in your own personal diet. You'll start observing other obvious macroscopic behaviors like "empty" vs "filling" calories that I find are, at least for me, significantly more valuable for weight management. They not only provide an upper bound for energy consumption relation, they provide a ground truth to tie back to my own body: how full or hungry I am after I consume said energy, how groggy I feel, etc. This ultimately, for me, leads to valuable dietary changes that give effective guidelines to proven end results. When I gained weight during college, this was the trick that, for me, has lead to the most valuable lifelong weight management. YMMV.