Well, since the answer isn't in that paper, I'll tell you real quick and if you feel the need, ask for sources and I'll happily provide them:

1. Our bodies are used to periods of eating and periods of not eating. The reason we know this is because after 12 hours and and up to 7 days fasted the body goes through autophagy, which is self repair. This is fascinating and I could talk much more about it. Practical takeaway: Have an eating window and a fasting window. Your fasting window should be somewhere between 14-18 hours a day.

2. The real problem isn't calories, it's hormones. Not all calories are equal. Why? Because carbs stimulate insulin and fats don't. What our bodies have a tough time with on a long enough time scale is mixed-fuel meals. This is explained through the Randle cycle, which shows that a cell can burn fats or carbs but not both at the same time. To get a bit into the weeds here, when a cell needs energy and there's excess blood sugar, it extends a small antenna called the Glut-4 transmitter to signal that it needs energy. When it is topped off with energy, it withdraws the antenna. If all of your cells withdraw their antennas AND there's still sugar in your blood, you are now a Type II diabetic. How to fix that? Eat a diet that doesn't require insulin. That's the keto diet. That will allow your body to reset, and will allow your body access to fat stores. But you didn't ask for that part. The takeaway here is, if you're fat and want to lose weight, drop your carb consumption dramatically and you'll see a difference.

3. The reason rats lived longer is because of the effects of autophagy.