I'm continuously occupied with thoughts on this subject. You will need to study your body, I was experimenting a few years and from that I know what makes me sharp and what doesn't. In my case - refined sugar in any shape or form is affecting me a lot in negative way and I can see results straight away. This also holds for food rich in carbs as well as anything that contains processed grains. And my problem is I found myself to be addicted to sweets and bread (cravings when I'm trying to cut these off). I'm not sporty type of person (and there are periods of time when I'm extremely loaded and working long hours).

But I'm also lucky that my wife is very much into the subject of healthy living and food/dietary requirements. And for about 6 years she is attending seminars about different types of food and what effect they have on our bodies. Through those seminars she found a few easy tips that worked for me (though I am aware they are only shortcuts that let me survive until I can do things properly, i.e. treat sport seriously in my life). I'll share them with you so maybe they will be a good start on your journey:

One of those tips was bulletproof coffee (original recipe by Dave Asprey though in principle it's mycotoxins-free coffee with raw butter and coconut oil - healthy type of fat). In essence your brain can burn either carbs or fat. Carbs are preference though after immediate energy spike body gets crash. If you avoid carbs for long enough (more than 12 hours, different depending on person) your body may go to ketosis - state where your brain can switch to burn fat - and that's where bulletproof coffee comes to the game - since most of it is fat.

Another tip was avocado - it keeps me filled (much less cravings) and in the same type it's healthy fat too!

Another one was to keep a bottle of water (high PH) with me all the time. I started doing this when I realised there could be whole day past by and the only liquids I would drink was coffee! I aim to drink 1.5 litre a day, this bottle stands on my desk so I reach and have a gulp every now and then. Our body is mostly build from water so it's helping to keep water level within levels allowing normal functioning (you will need to find how much is `normal` in your case).

I started testing above three on myself 3 years ago and get consistent result. Less crash from coffee, need much less coffee (essentially one in the morning and that's it), longer high-focus sessions without shaky hands syndrome (since I drink much less coffee). And local coffee shop started making bulletproof coffee about 2 years ago too which helped :-)

Another `discovery` of my own is I am really not benefiting late nights sessions (wow! though not so obvious when you are coding). If I stay late at night the very next day I'm less focused and generally less happy of the outcome when day ends. So I tend to shift from late night to early morning, which also made my family to benefit too.

Regarding "feeling of need" - I had this too, it goes away when you go into routine and find your own rituals that you celebrate each day. Morning bulletproof is one of my rituals :-) and it helps since my brain is focused on following my way - even if I smell coffee later during the day I'm not intimidated.

Good luck!