What does insulin resistance have to do with overweight and weight loss?

We observe all the time that some people seem to be able to eat anything and not gain weight, and others eat very little and are heavy.  The calories in/calories out dogma denies that this phenomenon exists, but we all know it does.  At the Packard pediatric weight control program, one of the most difficult things for the children there to handle was the fact that it seemed their peers could eat anything they wanted, including chips, candy, and soda, and be slim.  And they were right.

How is this possible?  How an individual will respond to the typical American diet is dictated by how insulin sensitive or insulin resistant they are.  The typical American diet is high in carbohydrates.  Carbohydrates cause the body to produce insulin to keep blood sugar in a normal range.  (An equal amount of energy consumed as fat causes virtually no change to insulin levels).  Some individuals are sensitive to insulin–they can process a given amount of carbohydrate with relatively little insulin release.  But some are insulin resistant–they require a lot of insulin to process that same amount of carbohydrate.

Insulin is also known in any biology textbook as “the fat storage hormone.”  Can you guess which individual is going to gain weight from the typical American diet?

Relative insulin sensitivity or resistance also explains how an individual is going to respond to different sorts of eating plans designed for weight loss.  The insulin sensitive individual can lose weight on a low fat, low calorie plan or on a low carb plan.  But the insulin resistant individual will find it very hard to lose weight on a low fat, low calorie plan:

“Insulin Resistance and Diet Success

In 2007, Gardner et al published a randomized, controlled trial called the A-to-Z Study involving 4 diets lasting a year given to groups of obese women[43]. At one end of this diet spectrum was the ‘Ornish diet’ which is very high in complex carbs and very low in fat. At the other end was the ‘Atkins diet’ (i.e., low carbohydrate). After 6 months, the women on Atkins had lost significantly more weight, but after 12 months they were still lower but not significantly so. Interestingly, blood pressure and HDL cholesterol were significantly better on low carbohydrate than any of the other diets, and this beneficial effect remained significant out to 12 months. After publishing this initial paper in JAMA, Dr. Gardner went back and examined his data based upon the subjects’ insulin levels before they started dieting. When the women on each diet were divided into three subgroups (tertiles) based on baseline insulin resistance, the results were striking. In the low carbohydrate diet group, weight loss was similar in the most insulin sensitive (11.7 lbs) and insulin resistant (11.9 lbs) women. However weight loss with the high carbohydrate (Ornish) diet was much greater in the insulin sensitive (9.0 lbs) than the insulin resistant (3.3 lbs) women. Thus the most insulin sensitive sub-groups of women experienced a similar weight loss when assigned diets either high (9.0 lbs) or low (11.7 lbs) in carbohydrate In contrast, the sub-groups that were insulin resistant fared very poorly when assigned a diet high in carbohydrate (3.3 lbs lost) compared to a low carbohydrate diet (11.9 lbs). Specifically, those women with insulin resistance lost almost 4-times as much weight when dietary carbohydrates were restricted[44].”

Phinney, Stephen; Volek, Jeff (2011-07-08). The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable (pp. 85-86). Beyond Obesity LLC. Kindle Edition.

They may lose some, like Juliana did, because a low fat, low calorie plan is almost certainly also a lower carb plan.  But the insulin resistant people are going to be hungrier than the insulin sensitive people on an Ornish-type plan.  Why?  The more insulin, the more the cells get the message to store available energy as fat.  The more that is stored as fat, the less is available to use, and the sooner that person will be hungry again.

I have already taken Dr Dean Ornish to task for publishing a misleading opinion piece in The New York Times blasting low carb eating plans.  He would also do well to pay attention to his patients who cannot comply with his eating plan because of hunger, or don’t lose much weight even if they do comply.   He might learn something.

 

 

Not getting fat because she’s lazy, but lazy because she’s getting fat

We all associate overweight people with low energy, and there’s a good reason for this.  But it’s not the reason you think.  People don’t get fat because they don’t move much; they don’t move much because they are getting fat.  The energy they could use to be active is being diverted to storage as fat.  The culprit is insulin, which is released mostly in response to eating carbohydrate, much less so in response to eating protein or fat.

When you are a parent, this lethargic behavior is extremely frustrating.  I remember vividly once when Juliana was about 9 and we were on vacation and she didn’t move from the couch all day.  I actually remember wondering what was wrong with her.  She wasn’t sick, but she didn’t look like she felt well.  At 3 in the afternoon I insisted that she go outside and do something, anything.  She didn’t want to.  I had to really push her, and I was trying to hide my anger as I did it.  Eventually she did so, reluctantly.

Now I know that going outside and moving was actually a huge effort for her, because she didn’t have much energy for motion.  It was mostly being stored in fat cells.

A lesson from ice cream

We live in the heart of Silicon Valley. Seven days after starting the low carb eating, Juliana took a field trip with her class to the Google campus in Mountain View.

Google has what they call the 150/15 rule.  The 150 is the number of feet you are from food anywhere on the Google campus, and the 15 is the number of pounds you gain your first year working there.    So, naturally, the field trip to Google included ice cream.

Juliana ate a scoop, came home, and lay on the couch the rest of the day.  She felt slightly nauseous. She had to cancel a homework appointment with a classmate. At first she thought she was tired because they had walked around Google so much. I didn’t think so.

The zap of sugar to her system caused a spike of insulin which in turn caused her body to store all the ice cream energy in fat cells, leaving none for Juliana to use.  After only 7 days of low carb eating, her system couldn’t handle a scoop of ice cream.  Then I knew we were really onto something.

Her grandfather had type II diabetes

I also remembered that Juliana’s grandfather, although healthy overall and not overweight when I knew him (he had been heavier when he was younger), developed diabetes in his 70′s, a few years before he died.  He was able to control it without medication by limiting his carbohydrate intake to less than 200 grams a day.

Type 2 diabetes doesn’t just appear overnight–it’s the end result of an ongoing process.  A person is classified as diabetic when their insulin response crosses a certain threshold.  But before it crosses that threshold it’s been approaching it for years.  And the stimulus that creates the insulin reaction is carbohydrate.

Juliana’s grandfather’s diabetes was a further clue that Juliana could be predisposed to carbohydrate sensitivity.  The effect of carbohydrate sensitivity is more insulin production in the body for the same amount of carbohydrate relative to a non-sensitive individual.  More insulin production causes weight gain.   If you or your child’s other parent is overweight, or his or her siblings or parents; or your siblings or parents; or if there is type 2 diabetes in either family even if no one is overweight, these are further indications that your child may have a low tolerance for carbohydrates.

Insulin: The Fat Storage Hormone

Gary Taubes explains that in any basic biology textbook, insulin is known as the fat storage hormone.  Its job is to direct your fat cells to store energy as fat.  If you produce more insulin than your neighbor from ingesting the same amount of food, you will also store more of that food energy as fat.

Carbohydrate provokes the release of insulin, in some individuals more insulin than in others for the same amount of carbohydrate.  That is why two people can eat the same food and exercise the same amount and one can gain weight while the other doesn’t.

It gets worse.  Call the weight gainer Jim and the weight maintainer Steve.  Jim will be hungry sooner than Steve.  Why?  Most or all of the energy in the food Jim just ate will have been tidily stored away in fat cells, instead of being available for Jim to use.  Jim will feel hungry again in response to the lack of energy.

Jim will also feel tired, because the food energy has been sequestered in fat cells rather than remaining available for use.

Protein and fat do not provoke insulin production to nearly the same extent as carbohydrate.  The energy that is eaten is not stored as fat; it remains available for use.  Controlling insulin production is the key to better energy and a healthy weight.  And the key to controlling insulin production is controlling carbohydrate intake.

Taubes concludes that the logical eating plan for weight control (and a host of other health benefits I haven’t described here) is one that limits carbohydrates to much lower levels than the USDA-approved Standard American Diet.