Yes, this. Taking a walk does nothing unless it is a 5 mile cross country power walk. A casual walk around the neighborhood isn’t going to induce weigh loss. Running 20 miles per week will not induce weigh gain, no matter what you eat. You can eat more (cake, doritos soda, red meat, pasta, bread, cheese) and the only result is you get faster. I know from experience. I actually had to cut back my training and start racing half marathons instead of marathons because I was losing too much weight and looking emaciated. I usually manage to put on about 10 pounds in the winter, but it disappears by the end of May by doing nothing different other than sweating in the heat.
Exactly!