A good, hard, training regimen is the only way to get a perfectly lean body, and it releases all those endorphins that make you feel awesome afterward. But by all estimates, a sound nutritional program accounts for around 80 percent of your results. What those don't account for is the power of supplements.

Add these 4 critical elements to your diet, and you'll supercharge your lean muscle gains, accelerate fat loss and improve your overall health.

1. Whey Protein

What it is: One of milk's two proteins.

What it does: Whey's primary characteristic is its digestibility. Once in the body, it breaks down quickly, swiftly sending its aminos to muscle tissue. This is beneficial because there are certain times of day (first thing in the morning, before and after workouts) when the lean whole-food proteins we normally recommend (eggs, chicken breast, lean steak, fish) digest too slowly to be effective. But whey doesn't deliver only protein. It contains peptides (protein fragments) that have been suggested to help increase blood flow to muscles, which is particularly helpful before workouts, so that muscles may receive more oxygen, nutrients and hormones right when they need them.

How to take it: Take 20 grams of whey protein (mixed in water) first thing upon waking, within 30 minutes before workouts and another 20 g within 30 minutes after training. And you can always have a scoop as a snack between meals.

How to take it: Take 200-400 milligrams of caffeine two or three times per day, with one dose 30-60 minutes before workouts.

2. Calcium

What it is: An essential mineral.

What it does: Just about everyone knows that calcium is intrinsically linked to bone health, but did you know that it's also required for muscle contraction? Without adequate calcium, muscles won't contract properly. And research suggests this unassuming mineral can also help spur fat loss. This may be because calcium decreases the amount of dietary fat that's absorbed by the intestines and suppresses a hormone called calcitriol, which is responsible for reducing fat burning.

How to take it: Take 500-600 mg of calcium twice a day.

3. Vitamin D

What it is: The sunshine vitamin.

What it does: New research keeps coming; most of it supporting Vitamin D's ample health benefits. Vitamin D is associated with greater muscle strength - interacting with receptors on muscle fibers to activate genes that increase muscle strength and growth. As a plus, D may help support fat loss, especially when taken in conjunction with calcium.

How to take it: Take about 2,000 international units of vitamin D twice per day at the same time you take calcium.

4. Green Tea Extract

What it is: The active ingredients in green tea, particularly the polyphenol epigallocatechin gallate.

What it does: EGCG blocks an enzyme that normally breaks down norepinephrine, a neurotransmitter/hormone related to adrenaline that increases metabolic rate and fat burning, keeping norepinephrine levels higher. Green tea extract also has been suggested to help support enhanced muscle recovery after intense workouts, as well as aid in supporting healthy joint function.

A good, hard, training regimen is the only way to get a perfectly lean body, and it releases all those endorphins that make you feel awesome afterward. But by all estimates, a sound nutritional program accounts for around 80 percent of your results. What those don't account for is the power of supplements.

Add these 15 critical elements to your diet, and you'll supercharge your lean muscle gains, accelerate fat loss and improve your overall health.

How to take it: Take 1,000 mg twice a day with meals.