What the Heck Just Happened?

Our bodybuilder suffered metabolic damage: a drastic slowing of the metabolism that is caused by excessive caloric restriction, cardio, and stress on the body. This issue particularly plagues female competitors.
Fat loss does not come as easily for the majority of women as it does for many men, and as a result, many resort to drastic measures in an effort to get shredded.
The unmotivated competitor will give up long before things get to this level. Yet elite, highly motivated competitors will push through and do whatever it takes to get lean. The attitude of "whatever it takes" is common in this sport.
Someone with this attitude often will not rule out starving themselves or doing several hours of cardio per day.
I'm tired of seeing bodybuilders, fitness women and figure competitors suffer and struggle with this condition. So I'm here to help inform you, before you become the next victim.

It's All about Survival ///

Let's clear one thing up right now. It is normal for the metabolism to slow down on any diet or calorie restriction. This is all due to metabolic adaptation.
As soon as our hypothetical competitor cut calories from 3,000 to 1,600, his metabolism began to downshift. Many people do not realize that the body uses calories simply through digesting and processing food. This is described as the thermic effect of food. The simple act of eating less causes lower energy output.

Once the body senses a loss of body fat, it will begin to lower thyroid levels and diminish nervous system output in an effort to stop the weight loss. Once further calorie cuts are made and cardio is increased, fat loss will resume again, and the body further lowers thyroid levels and nervous system output. It also lowers testosterone levels and raises cortisol levels, both of which eventually lead to muscle loss. Since muscle is a metabolically active tissue—it consumes calories simply to exist—the metabolism will drop even further.
So why does the body sabotage effort like this? It's simple: survival. If our bodybuilder ate 3,000 calories per day, cut his calories to 2,500, and his body did not have these adaptive abilities, he would lose weight continually without stopping until he eventually died. Luckily, nobody starves to death on 2,500 calories per day—even though it may feel like it sometimes. These normal adaptations are necessary for survival.
The human body is an amazing adaptive machine that always strives for homeostasis. Whatever condition the body is put in, it will strive to survive within that new norm. For a successful prep, you need to understand how to work with your body as much as possible, and understand that your body will automatically take measures in response to calorie intake or expenditure.

Getting Slow Post-Show ///

In my experience, metabolism crashes happen in cycles. People drive their metabolisms into the ground for their contest prep, leaving them seriously slowed.
Someone with a tanked metabolism cannot handle many calories at all. Yet after the show is over, most will tend to binge excessively as the months of restriction lift.
Their metabolism is not equipped to handle this level of calorie intake, and the fat gain is fast and furious. This leads to getting extremely heavy, yet the metabolism remains depressed.
I found that most competitors who prep incorrectly—to the point of having serious metabolic issues—do not get lean enough to place well.
As a result, many are not particularly pleased with their showing. This makes them eager to get back on stage and redeem themselves.
These competitors typically take little time off before prepping for another show. They begin their prep with an already lowered metabolic rate, too much fat to lose, and not enough time to lose it. The vicious cycle begins all over again.

5 Tips to Prevent a Slowdown ///

Luckily, there are several ways to prevent serious metabolic issues from occurring. The metabolism will slow a bit on any diet, but this does not and should not lead to extreme calorie deprivation and hours of cardio.
This isn't healthy, and in the end it won't get you lean enough. Here are the rules to follow for a better prep.

1 / Practice Patience

Fat loss should not be rushed. It takes time, and plenty of it. Aim to lose no more than two pounds of fat per week, and preferably closer to a rate of 1-to-1.5 pounds. This ensures that muscle loss is minimized. Muscle tissue consumes calories all the time. You don't want to cannibalize this metabolically critical tissue.
Another part of being patient is learning to make minor changes to the diet rather than massive cuts. As soon as you make a change, whether it be cutting carbs or increasing cardio, your body will immediately begin adapting to the change. Every change you make to increase fat loss is a tool in your kit. Do not use all of your tools in the first few weeks.
If fat loss stalls and you cannot cut calories any lower and already do hours of cardio per day, you're stuck. You need to save something up your sleeve for the end of the prep.

2 / Keep the Carbohydrates

If you want to get lean, you sometimes have to drop carbs to low levels. This does not mean that you should eliminate them.

Carbs increase cellular hydration, and therefore cell volume. When muscle cells are hydrated and have greater volume, this signals the body that it is in a satiate state. The body, sensing it is fed, keeps the metabolic rate raised. Obviously if carbs are too high, fat loss cannot occur, but for continued fat loss, carbs should remain in the diet.

3 / Utilize High-Carb Days

I believe carbohydrates are essential to keeping an elevated metabolism. Leptin is a primary reason for this. Leptin is a fat-burning hormone; its release is directly related to carbohydrate intake and body fat levels. Leptin serves many functions, including the control of energy expenditure.
As carbs get low and body fat levels dwindle, the body inevitably lowers leptin levels. Combat this (to an extent) by adding in high-carb days. A high-carb day once every 4-8 days can boost leptin levels; leptin is highly responsive to glucose metabolism.
Add high-carb days to boost leptin, and it will lead to a more positive hormonal profile in general. High-carb days can lead to higher levels of the thyroid hormone t3, as well as help to keep testosterone levels elevated, both of which can further your fat-loss efforts.

4 / Don't Cut Fat Too Low

Fatty acids must be available in the body to create cholesterol, which is eventually converted to testosterone. If fat intake is too low, there won't be enough fatty acids available for optimal testosterone production.
This leads to lower testosterone levels, which lead to greater muscle loss during prep. The two combine to lower your metabolic rate.
The body also has a built-in adaptive response to chronically low dietary fat intake. When it senses an extremely low intake of fat, your body naturally tries to hold on to body fat stores, since fats are at a premium. Moderate amounts of fat intake will ensure that calories are low enough for fat loss, but that the body does not perceive starvation.

5 / Reverse Diet

A reverse diet is where you add calories back into your diet slowly, much the same as when you cut them slowly in order to get lean. This will prevent copious amounts of adipose tissue from collecting within the first month or two after a show. Reverse dieting is essential to prevent the cycle of metabolic slowdown, or stop it if you are already in the situation.
Even the best contest prep in the world will lead to a significantly slowed metabolism. Conversely, the human metabolism can be raised by systematically, but slowly, adding protein, carbs, and fat. If you already find yourself with a crashed metabolism, then a long reverse diet is the best prescription to help get you back on track.

6 / Don't Get Too Heavy in the Offseason

Just because the show is over doesn't mean it's time to begin eating anything and everything. On the contrary, getting too heavy in the offseason is often how metabolic issues get started.
I already discussed how metabolic adaptations to excessive measures for fat loss can cause serious metabolic slowdown. New research shows that losing massive amounts of fat can cause a dramatic slowing of resting metabolism out of proportion to weight loss, even when fat-free mass is maintained. This metabolic adaptation may even persist during weight maintenance. Starting your prep at too high of a weight sets the stage for drastic measures that invite excessive metabolic slowdown.

So while all the other factors are still important, it all begins in the offseason. The days of gaining 60 pounds in the offseason and trying to lose it all in a single prep are over. Those who are willing to do what it takes even in the offseason will be the ones who are rewarded on show day.

7 / Have a Plan and Stay Informed

Don't get me wrong: Doing what is takes to win isn't a bad thing. The problem is that too few identify what it actually takes to win. When dieting for a show, blindly working hard is not the answer. Just because you work as hard as or harder than someone else doesn't mean it is more effective.
It's a lot like running a marathon. While a marathon is 26.2 miles, some people in bodybuilding would run their sport's equivalent of 35 miles just to say they worked the hardest. To top it all off, most of them would be running in the wrong direction! They worked harder and still placed last.
Working hard for the hell of it won't cut it. Get a plan and then bust your ass! Your metabolism will thank you.