Energy isn’t a problem just wish there were more hours in the day 
On a more serious note tho, diet is, imo, key. We have evolved to function best on a specific type of diet - a species appropriate diet - and a great place to start is the Palaeolithic diet. If you’ve never followed such a diet before you will probably be quite (pleasantly) surprised by it 
I often say try it (strict) for 3 months - what’s 3 months of your life when it could be one of the best things you ever did? And that doesn’t have to be on blind faith either, there are thousands upon thousands of people saying how it’s helped, and even more when speaking of diet changes in general. Diet really is the key in the majority of cases imo. The paleo is a great place to start because it’s extremely popular - so lots of recipes on line 