Man 2.0 Engineering the Alpha

is amazingly proficient at adapting to the various stressors in life, including severe caloric restriction. The body quickly recognizes the caloric deficit and then promptly makes the necessary adjustments to maintain homeostasis.
    This is an evolutionary adaptation that has helped our species survive in times of famine—awesome for that, but not so desirable for people who want to get lean. If you cut calories, your body will eventually adjust and hold on to more fat, which is exactly what you’re trying to avoid.
    We just told you that you’ll be training harder, eating more on those training days, and eating less on your off days. As with everything in this book, there’s a reason for our madness. When you follow a traditional diet of just eating less, this is what typically happens inside your body.
    Decreased Levels of T3 and T4
    T3 and T4 levels (thyroid hormones that play a major role in the regulation of metabolism) in underfed individuals mimic and can actually cause sick euthyroid syndrome. In short, low levels of these hormones are anything but desirable for individuals seeking to lose fat mass.
    Decreased Basal Metabolic Rate
    The overall decrease in metabolism, or basal metabolic rate, is largely due to the aforementioned decrease in output of T3 and T4; however, a host of other factors also contribute to the downregulation of the basal metabolic rate. In essence, metabolic rate is decelerated in an attempt to balance energy expenditure with caloric consumption, thus preserving more fat mass. So if you eat fewer calories, your body does what it can to burn fewer calories.
    This effect, combined with the one above, is the reason for what we colloquially term starvation mode —your body thinks you’re starving, and it does its best to keep you alive.
    Increased Levels and Half-Life of Cortisol
    Severe dieting both spikes and extends the half-life of cortisol. We mentioned that cortisol is a catabolic agent—when elevated for long periods of time, the catabolic effect will be directed toward your muscle. This is clearly not optimal for individuals who wish to retain lean muscle mass while attempting to lose fat. Interestingly, the serum cortisol levels associated with malnourished (underfed) individuals parallel those linked to individuals suffering from clinical depression.
    Decreased Serum Leptin Levels
    Generally speaking, there’s a positive relationship between leptin and the amount of fat mass you’re carrying. However, certain studies have shown dramatic decreases in leptin when caloric intake is highly restricted, independent of fat mass. When low levels of leptin are transmitted to the associated receptors of the hypothalamus, the hypothalamus then begins to send out various regulatory signals to the rest of the body in an attempt to decelerate fat loss and decrease energy expenditure. Or in English: low levels of leptin slow your ability to lose weight by turning your metabolism down a few notches.
    It almost seems backward: the better shape you’re in, the harder it is to look even better. In other words, the more you move away from the weight that your body is used to (called your set point), the more your body adapts to resist your transformation. Even though individual set points can vary greatly, one thing remains constant: the leaner you get, the worse the aforementioned problems become. But if you can change your set point by staying at a lower body fat for a longer period of time, your body will adapt and make fat loss easier—at least compared to when your body constantly lives in an overweight state.
    The main reason lean people have extreme difficulty shedding that last bit of stubborn fat is that their metabolisms have hit rock bottom. Cortisol is freely running its course while T3, T4, and leptin are all slowed to a trickle, like blood to the nether regions of an eighty-year-old man in the days before Viagra.
    However, there is hope—and that hope lies in cheat days.

    THREE HORMONAL BENEFITS OF CHEAT DAYS
    “All you need is love. But a little chocolate now and then doesn’t hurt.”
    — CHARLES SCHULTZ
    1. Increase in thyroid hormone output
    When your body is in a caloric deficit, you produce less T3 and T4—both important thyroid hormones that play roles in the regulation of metabolic rate. A cheat day or strategic overfeed can help increase these hormones.
    2. Increase in twenty-four-hour energy expenditure
    A caloric surplus from a cheat day causes your body to