Exercise and weight loss are often explained as fitting together as a hand and glove model; in that, one without the other is thought to be ineffective. While this idea sounds credible, many who engage in consistent and aggressive physical activity often report the opposite: weight gain. Such weight gain is frequently explained away as simply the net effects of increasing muscle mass (a more dense tissue) concurrent with their fat loss. This may not always be the case.
The body provides energy to sustain itself (breathing, pumping blood, repair, and activity) from three main sources: carbohydrates, fats, and proteins. While all three can be used as an energy source, not all energy pathways operate at the same speed. In high intensity activity, the majority of energy is derived from carbohydrates with smaller quantities coming from fat and protein. Such activity does burn calories, but simply burning calories may not ensure weight loss. Weight loss comes from sustaining a calorie deficit over time.
It is common that when people begin a weight loss regimen they may aggressively restrict their calorie intake via counting calories or simply reducing portion sizes. Initial days of restriction are overshadowed by the idea that “if moderation leaves me a little hungry and only causes moderate weight loss, I might as well get it over with by being really hungry, and see faster weight loss.” This type of restriction alone is enough to be NON-SUSTAINABLE in the long term.
Compounding this problem is that many also begin an intense regimen of physical activity. At high intensities the calories being burned come from the body’s reserve of carbohydrates, of which very little is stored, 1500-2500 calories at all times. This intense burst of activity leaves the person carbohydrate depleted and feeling VERY HUNGRY, which causes the hunger response to prod them towards replacing the carbohydrate calories expended. This may result in the person returning from their workout, consuming a small meal, and still finding themselves starving afterwards. The body continues to express its frustration until its lack of carbohydrate stores is replenished. Eventually a person yields to their hunger with compensatory eating which counterbalances or overbalances the calories they burned during their workout, resulting in weight gain.
A person desiring to lose weight and be physically active should therefore engage in an exercise plan that is of a sustainable and of a moderate intensity. Even though moderate activity will not burn nearly as many calories as intense activity, it can derive the majority of its energy from fat stores, (which is what most of us want to reduce in the first place) and leave the majority of the carbohydrate stores intact. This can allow a person to pursue physical activity without engendering a large spike in hunger levels. Such a moderate attack combined with a well-constructed meal plan can allow the person to achieve meaningful weight loss and actually ENJOY physical activity for the rest of their lives.