How Fast Should I Lose Weight

Over the past couple of months, I have been increasingly active on the "Forums" at bodybuilding.com. The forums cover every fitness and sports related topic imaginable, but as you can surmise, with an overall bodybuilding focus, the subject often comes back to the topic of leanness, and losing weight. Conditioning, after all, is usually the difference maker in bodybuilding competitions.



What I often see in these long, "threaded" discussions is people trying to lose too much weight far to quickly. Even those never contemplating a pose-down on the bodybuilding stage, often set about their weight loss efforts with weekly targets that almost guarantee long term failure. I see this constantly among my own clients and workout partners.

There are several issues with trying to lose weight too quickly. First, and maybe most importantly, if you lose more than 1 pound per week, you're almost guaranteed to be losing a significant amount of muscle as you lose body fat. This 1 pound per week, or 500 calories per day, limit was recently confirmed through a well constructed university study, and echoes what I have observed for years.

For the athlete and the bodybuilder, this is an absolute deal breaker. Even the non-athlete does not want to lose muscle mass while dieting, however, as muscle is one of most important contributors to overall metabolic rate. The more muscle you have, the more calories you burn, even while sitting still.

Second, losing weight too aggressively adversely impacts the endocrine system. In short, once you hit a certain calorie deficit, thyroid function will begin to decrease. This is the body's way of protecting itself by lowering metabolism during times of starvation. Just where that threshold is varies individually, but my personal observations of myself and clients says that it's somewhere between a 500 and 1000 calorie deficit per day. In this case, it pays to be conservative. Once thyroid function has dropped it can take months to rebuild it and you're super susceptible to fat accumulation the whole time.

Losing weight too fast can also effect levels of leptin and ghrelin, digestive system hormones that provide feelings of satiation and hunger respectively. When these two hormones are "out of whack" it becomes almost impossible to avoid periodic bingeing. This, on top of muscle loss and decreased thyroid function is why most severe diets are paths to failure. Again, once these hormones are functioning less than optimally, it can take months of careful diet manipulation to rebuild normal levels and feedback loops. Some folks never get back to normal.

Finally, once you have ratcheted back to a certain level of caloric input, the amount of glucose available to the frontal lobes of the brain is diminished. It's this supply of glucose that powers what most would label "will power." When that power supply is reduced, your ability to stay focused on goals and/or resist temptation is just not there. It's no wonder most dieters report an inability to control their emotions, suffer depression, and often succumb to an eating frenzy when faced with tempting foods. For those interested in more on this topic, two recent books on "Willpower," by professors from Princeton (Baumeister) and Stanford (McGonigal) highlight this glucose/brain linkage to dieting success.

So, looping back to the original question, "How fast should I lose weight?" the overwhelming evidence is that is just does not pay to try to lose more than 1 pound per week. This equates to a 500 calorie per day deficit. Trying to do it faster will just backfire.

As well, and most will not want to hear this, I recommend not dieting for more than 12 weeks straight, at this rate. Going longer than that, even at a 500 calorie per day deficit, starts to elicit some of the adverse effects ascribed to aggressive dieting.

This 12 weeks should be followed by a 8-12 week maintenance phase, allowing all systems to return to baseline functioning, before another round of dieting can begin.

What that means to a bodybuilder is that you'd best not be more than 12 pounds above contest weight, before starting pre-contest dieting (assuming you don't want to lose muscle) and for the average dieter it means, no more than a 24-36 pound weight loss over the course of a year (two-three 12 pound, 12 week rounds of calorie reduction).

On a positive note, this rate of fat loss is relatively painless and most importantly, assuming good eating and exercise habits are built simultaneously, the fat loss will be permanent. Go slow, be steady, think long-term. That's the only way to make it work.