Comment by mtmickush

It is a very valid point that dieting / food intake converts to calories way more drastically than exercise.

The article is taking this one step further though and saying those 300 calories burned by exercise are simply conserved elsewhere throughout the day automatically by your body.

The claim then is that if you exercise and burn 300 calories, but eat an extra 300 to offset it you won't end up at a neutral state and instead will gain weight as if you hadn't exercised at all.