There aren’t any single foods that can independently change any of these. Losing weight if you are overweight can help with energy; getting adequate rest is important for concentration. Your best bet is to eat a healthy diet that is focused on fruit, vegetables, whole grains, seafood, beans, & nuts. Limit fried foods, bacon, cheese, fatty meat, sweets like pies, cakes, cookies, donuts, candy. Spacing food, including protein foods, throughout the day in 5-6 meals/snacks as opposed to one or two large meals is also important for controlling high and low levels of blood sugar which might impact energy levels. And then there is the aging process itself. Some things, like levels of testosterone, decline as you age, which can have an effect on the changes you’ve described.