From the comments:

 The mid section has always been my concern. No matter what size I have been, I have never been happy, due to the quoted statement above from this weeks blog. I have also had 2 children in the past 8 years, 21 months apart, so I am coming to terms as to what my body is supposed to look like, not to mention me turning 41 this year. Have you or will you be writing up what a “healthy midsection” typically looks like?

For a lot of reasons abs capture the imagination.  We instinctively think they’re sexy, and the notion isn’t unfounded.  Abdominal health is a close proxy for health in general.  People with guts are much more likely to have hypertension, diabetes, develop certain types of cancer, and be susceptible to metabolic syndrome in general.

And the association isn’t anecdotal.

People with large amounts of abdominal fat are usually resistant to leptin, an endocrine hormone that protects your internal organs from blood lipids.  Fat is fine…..as long as it’s stored in fat cells.  When it starts to grow on your heart, liver, and other organs it begins to wreak havoc by secreting a variety of hormones they’re not well equipped to regulate.

But with that said, how far should you go before you’re satisfied with your midsection?

In general, large midsections are indicative of very poor health, great midsections are good indicators of tip-top health, but abs are not reliable health signals for people who are already in good shape.

Some Important Facts

When thinking about the importance of abs, and particularly how they look, use the following points to guide your thinking:

• Your genes probably determine around 50% of your body fat distribution
• Practically everyone experiences a gradual decrease in endocrine hormone sensitivity, allowing for an increase in fat accumulation as you age
• The benefits of weight loss and fat accumulation are J-shaped.  I.e, being really under or overweight is very bad for you, but the benefits of weight loss begin to taper off once you get into a healthy zone
• It’s better to be flabby and fit than lean and out of shape.

Let’s discuss the importance of each of these points in more detail.

Six Packs Are Largely Genetic

Most people can and should strive to reduce their midsection if it’s excessively large.  In addition to making you feel better about yourself, excess visceral (abdominal) fat closely tracks insulin resistance, pre-disposition to diabetes, high cholesterol and tri-glyceride levels, and other facets of the metabolic syndrome.

However, once your body fat percentage falls into a healthy range (around 6%-13% for men and 10%-20% for women), the differences in how your body deposits fat are controlled by your unique assortment of alleles that control how your body secretes growth hormone, gets hungry, and metabolizes fatty acids in your blood.  By as much as 50%.

Lots of studies have been conducted on how the physical traits of twins change over time, and even when they are separated at birth their anthropometric traits show remarkably similar progressions throughout their life.  So once you’re healthy the difference between having a little flab and looking like a greek statue is in the hands of mother nature.

If you’re one of the lucky few who’ve won the genetic lottery and have been biologically programmed to generate higher levels of glucocorticoids when you sleep than the rest of us, congratulations.  You’ll enjoy yourself more when you go to the beach and have an easier time getting dates.  But for the rest of us, moderate differences in abdominal flab don’t mean too much once we’re already fit.

Flab is Destiny

Excess abdominal fat is largely due to an acquired resistance to an endocrine hormone called leptin.  It’s a powerful hormone that regulates fat storage and hunger, and one of its biological functions is to protect your organs from lipotoxicity.  It works in conjunction with insulin to promote energy storage and help your body flip-flop between feast and famine.

Due to slowdowns in metabolism and decreasing muscle tissue, a gradual decrease in sensitivity to leptin and other energy sensing hormones is all but inevitable.  Old age isn’t a sentence to obesity, but father time eventually blunts all our senses, and for this reason a small but gradual softening of your waistline is not a sign that anything is wrong.

Health and Abdominal Fat Are Not Always the Same

The growth of fat on your body happens for a variety of reasons and is not always a great indicator of how healthy you are.

Think to yourself……do you know of anyone who’s great at sports but always seems to be carrying a lot of extra weight around?  Chances are you do.  I have a few friends who look like they should lose 30 pounds but can energetically play basketball for 45 minutes and are usually the best players on the court.

Those people are doing better than their skinny peers who are out of shape and smoking two packs of cigarettes a day.  Physical fitness is a better indicator of how healthy you are than your weight.

Here’s a useful graph that illustrates how physical fitness effects mortality for people with various eating habits from the Aerobics Center Longitudinal Study:

This is from an exhaustive study that examined the health outcomes of 25,000 different people at various weights and cardiovascular fitness.  The take home point is that in the long run being fit is a better predictor for your health than your weight, so it’s most important to make sure you’re in good shape regardless of your weight or belt size.

Where It Ends, Where It Stops

Your abs are very important to your health……up to a point.  But once you cross a certain threshold shedding additional ticks off your body fat percentage has more to do with you wanting to get a certain body than it does with attaining particular health outcomes.  That’s fine, but for most people going the last mile to get that six pack isn’t necessary.  Being flat tummied is good enough.