I am turning 40 soon and make sure I consume lots of fiber to keep my cholesterol down. It helps according to my last blood work. I eat lots of beans and veggies and MEAT. But, I limit my red meat/beef.
About the time I turned 40 my metabolism slowed, and my energy levels dropped. You'll also want to start having your PSA and Testosterone tested regularly.
I enjoy Scotch, red wine (actual health benefits when drank with moderation), and the occasional super-rich Stout / Sour / Porter beer. Scotch is lower in calories than many other "hard drinks". I extremely heavily restrict alcohol consumption. Most of the time I'd rather eat my calories.
We eat raw vegetables every day (I have at least one "dry" ... no dressing ... salad a day and typically 2-3 cooked veg with entrees). People drench their salads with "dressing" which harbors enormous fat and calories. I use a little fresh cracked black pepper or organic salsa (when we add avocado and limit veg like broccoli and cauliflower) as a "dressing" .
I've been trying to reduce my meat intake. Strict 4oz (or less) beef portions and 4-6oz chicken or fish. My wife hates fish, but I've been forcing it on her for 11+ years so she's gradually hating it less.
ETA: We also use almost zero "processed" products. 99% of what we eat is organic, and unprocessed. This can make a big difference.