In many mainstream diet strategies, calories are considered king. The mantra: eat fewer calories than the body needs, and then watch fat melt away. Seems straightforward enough.
As far as bodybuilders are concerned, though, merely dropping a few unwanted pounds is not generally the goal. No, it's all about getting ripped, so that every ounce of muscularity and striation pops through paper-thin skin. So, is the formula that simple? Is calorie counting all there is to it?

Far from it, in fact. When the goal is to get extremely lean, calories matter, but there are also lots of other factors to consider. The goal of
reducing bodyfat to absurdly low levels causes a struggle inside the body; metabolism, the calorie-burning "engine", slows. The result is a
mathematical dilemma: the longer or harder you diet to achieve your goal, the more your metabolism adapts — and decelerates to a near crawl.
If you were to exclusively follow a calorie-counting formula, eating fewer calories than the body requires, you would never achieve crystal-clear muscularity with little or no bodyfat. For starters, strict dieting can cause a drop in thyroid hormone levels.

Thyroid hormones drive metabolism, so even a mild decline can be dietary suicide. Ironically, eating, as in eating a lot of calories, can have the opposite effect, making thyroid hormone levels rise.
This is why I suggest that dieting bodybuilders use an undulating pattern, following a strict calorie-controlled diet for three or four days, with the fourth or fifth day set aside for a much higher calorific intake. This ensures the overall calorific intake is still somewhat low, but includes a day when calories are much higher. The higher calorie intake keeps the metabolic engine from downshifting. For example, a common diet strategy for a 200-pound bodybuilder might comprise four days of 1,800-2,200 calories, with an increase of several hundred calories on the fifth day. On average, over a few weeks, this would be a moderately lower-calorie diet, but, much more importantly, it would not disrupt the metabolism.
There's more. Low-calorie dieting for extended periods without taking a break can cause a change within fat cells. Hormone-sensitive lipase (HSL) is an enzyme that unlocks fat cells and allows bodyfat to be burned. However, over time, HSL levels flatline when calories remain low. What makes HSL move back up to favourable levels? The answer is eating. That's another reason to avoid stubbornly sticking with the simple premise that eating fewer calories will consistently result in rock-hard muscularity.
An important factor in all of this is anabolism. If you can maintain an anabolic state while dieting, you'll get ripped to shreds. That's because anabolism, the building of muscle tissue, demands calories. Some would argue that to maintain an anabolic state, a bodybuilder must eat more calories than he burns. Not so. To stay in an anabolic state, the body needs energy and lots of it, but much of that can come from energy reserves, otherwise known as bodyfat. In short, you can't change fat into muscle, but you sure can build muscle using fat. The muscle-building process can feed off your bodyfat to support growth. The big problem with calorie counting and cutting is that eating less nearly always compromises anabolic status.
When calories go down, it's hard to keep muscle. Protein, however, can serve as a saviour. Generally, protein needs rise at the start of a diet, and then continue to rise every week during the diet. Here's why: chronic lower-calorie dieting creates a condition where the body becomes more efficient at burning protein, even on diets that include days when the bodybuilder eats significantly more calories to avoid a metabolism slowdown. Lowered glycogen stores also necessitate increased protein intake. When muscle glycogen reserves stay low, which occurs during all diets that restrict or control carbohydrate intake, the body burns more protein.
One way to sidestep the burning of muscle is to consume more protein from egg whites, chicken, turkey, fish and lean meat, as well as low-fat dairy and protein powders, starting three or four weeks into a diet plan. The added protein blocks the breakdown of muscle tissue by acting as a sort of sacrificial lamb. Instead of burning muscle, the body burns the extra protein. In essence, you preserve muscle, maintain an anabolic state and keep your metabolism heading in the right direction.
Keep in mind that adding at least 100 grams a day of protein to a diet will increase the total calories you'll eat. If you were consuming 1,800-2,200 calories a day, adding another 100 g of protein will bring that daily total up to 2,200-2,600. You will be taking in more calories, but you should be happily experiencing a continuous loss of bodyfat. In our world, that result is king.