From Dr. Teeple:

Nutrition is key to maintaining your overall health - as well as maintaining a healthy T-Level. Your diet should consist mostly of low-carbohydrate foods, with an emphasis on good proteins and vegtables. 

Protein is essential, I try to eat my body weight in grams of protein every day to maintain muscle mass. An easy way to count protein grams is that a "deck of cards" portion of any protein (beef, poultry, fish) is equal to 20 grams of protein. As a rule, your body can not utilize more than 40 grams of protein per every two hours so it is important to try to have frequent, small meals throughout the day. 

Healthy Fats are important for your body to produce Testosterone. Omega 3 Fatty Acids found in fish and flaxseed as well as a small amount of saturated fats are key on a daily basis - good sources are pistachios, almonds, and peanuts.

Vegetables. Eat lots - especially the green leafy ones, broccoli, cauliflower, kale, and brussel sprouts. 

Zinc. You've probably heard stories about how eating raw oysters is a sure ticket to a strong libido. The stories have an element of truth. Zinc is important to the maintenance of Testosterone. Oysters have more zinc per serving than any other food; but if you don't like oysters then consider red meat and poultry, as well as beans, nuts, whole grains and dairy products.

Vitamins. It is a challenge to get all the vitamins and minerals we need daily. I take a daily supplement  that includes vitamins A (which decreases the production of estrogen in the testicles), E (stimulates production of sex hormones), C (enhances pituitary function, which can help raise T levels), and B6 (helps decrease the secretion of prolactin) as well as a good daily dosage of zinc - all of which help in T production. To reduce the body's estrogen level, I recommend a 50 milligram dosage of zinc, three days a week.

Drink Water. I'm a Urologist, remember? It is essential for everyone to get a minimum of 2 to 3 liters of water everyday.

Combining proper nurition with exercise is a sure-fire way to be as healthy as you can be.