Ho hum, another new day, another old myth.
Here are the main points :
1] The current study contributes little to what we already know. You cannot draw from this study any conclusion that being overweight is a protective factor for longer life.
2] Increased weight, even a quite small increase, is correlated with adverse health outcomes, such as increased accessing of health services [eg hospitalisation rates] when compared to people who are not overweight.
3] Eat less, eat more plants. The simplest way to stack the odds of health a little more in your favour.