Discussion: I'm pretty overweight. The GP told me that lean people are healthier. I'm not convinced he's right?

Let's get some order in what your doctor was probably trying to explain. The conclusion is that it is difficult to draw unequivocal conclusions!

Healthy people usually maintain the optimal weight for their body structure. (They are not necessarily thin.) Obese people are often unhealthy, such as being overweight due to an unhealthy lifestyle and poor nutrition. Medium overweight regarding their age (who are a large part of the population), are not necessarily healthy but are also not necessarily sicker than others. Thin people are also not necessarily healthier than overweight people. Good health is a combined result of lifestyle, environment, nutrition, and genetics.

Link: Practical tips for long-term weight loss.
https://www.sf-healing.com/page/214 (Copy & Paste)