They're saying a bit of both.
The rations here will only work for you, if you literally sit and do nothing all day during whatever is happening. If you move around, need to work, etc, they aren't worth it due to calories. Sure, if you're like me and have a little insulation on ya, it's not horrible, but after about 2-3 weeks, these just aren't going to cut it. These rations are typically setup with the amount of calories diet food has...
In a situation where you're working hard physically, you're going to want more than 2000 calories a day, or more - it's an arguable subject depending on how much physical labor you're doing.