I am in my late 40s. Last fall, I switched from a SAD to a kind of modified low-carb-ish paleo in order to drop 15 pounds (which I did quite easily). I no longer eat processed foods, nearly all of my produce and meat now comes from local farmer's market (grass fed/organic/etc). I do still eat some organic pastured dairy (yogurt, butter, cheese) and minimal grains (about 1/2 slice of kamut or spelt bread a day, no modern wheat). I have about 1/2 oz of chocolate a day, no other sweets or sugar. I eat lots of fruit and veggies, about 10 eggs a week, liver at least once a week, sweet potatoes & regular potatoes, rice every so often. I eat approx. 25% carb, 18% protein, the rest fat.
I also sit less / move more. I spend about 1/2 my working day at a standing desk. I walk most days, or swim a few laps, and do relatively gentle weight lifting / kettle bells several times a week.
In almost every way, I'm healthier than I was when I started. My lipid panels are excellent, my Vit D status is good, my skin is clearer than it used to be (long term eczema: gone!), my weight is normal, I rarely get sick. I fall asleep easier and almost never wake during the night. I generally have more energy.
I do take a scant teaspoon of Natural Calm every night before bed -- it is one of the things that helped me start falling asleep faster than I used to. It is the only supplement I take regularly other than Vit D caps in the winter. I track my nutritional intake on FitDay, and should not be deficient in anything else.
BUT, I used to sleep about 8 hours and wake up pretty easily in the morning. Now, if no alarm is set, I'll easily sleep 9 or 9 1/2 hours, and still wake up groggy. If I have to set an alarm, it is really hard to wake up after 8 hours.