Fat Set-Point
Understanding the Fat Set-Point:
Relative Bodyfat and Partitioning
In my previous series of articles, I talked about maximizing nutrient partitioning and the significance of insulin, adrenaline and site-specific fat. One more factor that can really impact nutrient partitioning is how much bodyfat you currently carry, relative to how much you normally carry.
If you’ve ever dieted down to contest-lean levels, you’ve probably noticed how differently your metabolism, your body, and even your psychology function depending on the intensity of your diet and how much fat you lose. It’s generally much easier to lose fat at the beginning of a diet than it is when you’ve reached competition level leanness. As your body composition changes, so does your metabolism and the ease at which it loses fat and builds muscle. I call this the metabolic status.
The metabolic status refers to how well your metabolism and various positive hormonal measures are currently functioning, relative to how well they’re capable of functioning. It’s influenced by factors such as caloric intake, diet composition, meal timing, exercise, stress level, and sleep habits.
For athletes such as Figure competitors, however, the biggest factor is your fat set-point. This is your level of bodyfat relative to your "normal" or "comfortable" level of bodyfat. Think of it as your bodyfat thermostat. Generally, partitioning is better at lower bodyfat levels. Lean people tend to have higher relative metabolic rates, they respond with increased non-exercise activity thermogenesis when they increase calories, their appetites are more easily controlled, and they have better natural partitioning. When lean people gain weight, they tend to gain more muscle and less fat.
Fat people, on the other hand, tend to have lower relative metabolisms, their appetites are more difficult to control, their metabolisms respond with a decreased thermogenic response to increased calories, and their partitioning is worse — so when they gain weight they tend to gain more fat than muscle.
The benefits of being lean should be obvious. The one major caveat to this, however, is that there’s a big difference in the metabolic functioning and partitioning between someone who’s naturally lean, and someone who’s dieted down to be lean. Not understanding this difference is a big mistake when making dietary recommendations and observations of metabolic function.
Lean people who’ve had to diet to get there often have worse metabolisms than someone who’s naturally lean, and in many cases will have a metabolism even worse than a fat person’s. That is, their bodies are functioning in a manner that makes them more susceptible to weight gain. A dieted-down lean individual won’t necessarily start piling fat back on without any excessive eating, but it’s more difficult for him or her to keep that lean body than someone who’s never had to diet to get lean.
As an adaptation to weight loss and dieting, a dieted-down lean person will have lower thyroid levels, lower HSL (which helps fat to release) activity, increased LPL (an enzyme which promotes fatty acid storage) activity,], a lower thermogenic response to increased calorie intake, and increased hyperinsulinemia. All these tend to either decrease energy expenditure, increase hunger, or make it easier to gain weight.
On the other hand, a naturally lean individual’s basal metabolic functions work in a way that makes it easy to stay lean: When they increase calories, their thermogenesis ramps up.
Weight Loss and Partitioning-
When losing weight, the same partitioning dichotomy between fat and lean people exits, except in reverse. Here, fat people have a big advantage. A fat person will lose more fat and less muscle than a lean person, and can get away with larger caloric deficits. They can get away with more extreme dietary measures without any ill effect.
That’s why a person trying to go from 40% to 30% bodyfat can lose fat and actually gain muscle slurping down an 800-calorie-a-day liquid diet with barely enough protein to satisfy a pigeon, while a person trying to go from 12% to 8% could never do that without losing a lot of muscle in the process.
Understanding this is important in determining your optimal off-season bodyfat percentage and maintaining dietary and exercise habits that allow your metabolic status to be optimized most of the time. If you get too lean (for you), not only do you easily put on fat, but you’re also hungry all the time, moody, and cold. Get too fat (for you), and you start to get lazy, and partitioning takes a nose dive.
You might temporarily drop under your optimal range for a competition, or go up a bit during the holiday season, when all those goodies and family gatherings are unavoidable, but the key is to maintain a healthy range most of the time. So what’s an optimal range? This point will vary from person to person and accurately identifying this point is the specific topic of a later installment in this series; but for men, metabolism is generally considered pretty optimal around a DEXA measured level of 10% bodyfat or around 20% for most women.
Above 15-17% for men and 25-27% for women, and things start heading south.
About the Author
Jen Heath is an ACSM certified personal trainer, professional natural bodybuilder, and mother of four children. She runs a successful online coaching business, through which she helps women alter the course of their lives, and achieve the lean, muscular physiques they desire. You can also find her here.
December 16, 2008 at 4:34 am
I have a friend who I am trying to assist in losing weight. He is fat but not obese. Should he go on an extreme diet for the best results?
December 23, 2008 at 1:59 pm
I do not think so.. I don’t believe that would do anything other than help temporarily… and in the end the weight would all come rushing back. If or when people especially highly overweight people go on extreme diets, they fall off because it is too restricting, too intense and too unsatisfying to be done and stayed on long term.
I will write more on this in a blog soon- Bare with me