"People tend to assume that if they eat as little as possible, they will naturally lose weight. That's not true!"

Much misinformation exists about diet, age in regards to resting metabolic rate, usually from the mass media and from ill informed individuals. Does your daily diet and age really affect my metabolism rate? Or would is it just another myth from mass media advertisers? To learn what is metabolism and what it constituent, read one of our earlier articles, entitled, "What is Metabolism and does Resistance Training accelerate it?".

What Effect Will Diet Have?

What you eat contain calories, it only depends on how much is your intake. To lose weight, an individual must burn more calories than he or she consumes, and to gain weight, an individual must eat more calories than he or she burns. It's a universal equation that applies to everyone and despite years of research, the treatment of obesity continues to revolve around the seemingly simple concept of balancing calorie expenditure with calorie intake (1).

"For you to lose or gain weight revolves around the simple concept of balancing calorie expenditure with calorie intake."

Thus, people would have the assumption, that if they eat as little as possible, they will naturally lose weight. But there is another loophole to this equation that and that it influences your metabolism. Very low calorie diets often fail because not enough calories are being consumed and this feeding restriction can diminish metabolic processes. It's unhealthy and it actually triggers the body to suppress its RMR by as much as 20% (Hill 2004).

Our body is amazing in adaptation and it goes to work as if it is in a state of famine. This obviously doesn't apply to our current society, but it does in the time of our ancestors. Benardot and Thompson in 1999 found that the body increases metabolic efficiency by burning less calories to do the same amount of work compared to an adequately fed individual. In additional, to a reduced metabolism, the body that is low on carbohydrates would start to use some protein as a source of energy, rather than for building and repairing muscle from resistance exercise. Muscle mass would be reduced, as muscle is the body's greatest source of proteins. Thus, low-carbohydrate diets are not recommended for individuals who train to enhance muscular fitness levels (Benardot and Thompson, 1999).

So will Age affect Resting Metabolic Rate (RMR)?

Elia (1992) found that the metabolic rate per kilogram body weight in young children is about two times greater than that in adults. As we age, our RMR decreases. This is due to the organs (heart, lungs, liver, etc.), which account for a large percentage of RMR, are of a larger proportion in a young person's body compared to an adult. A 25% drop in RMR between the ages of 6 and 18 is expected as more adult proportions are reached. Our RMR would continue to additionally drop approximately 2-3% each decade due to the loss of fat-free mass. But not all news is bad! This vicious trend can be minimised with regular resistance training exercise throughout the aging phase of our lives.

Additional References:

(1) - Blackburn Blackburn, Phillips, & Morreale 2001; Alford, Blankenship & Hagen 1990; Golay, Eigenheer, Morel, Kujawski, Lehmann & de Tonnac 1996