Thursday, December 29, 2005

Fatty Diet Follies

At least 89 articles appeared in the press since yesterday, claiming that research shows a diet that is high in fat can disrupt sugar levels and trigger diabetes. In the LA Times' article is titled, "Enzyme Study Links Fatty Diets to Diabetes."

The opening sentences are pretty convincing: Diets high in fat can disrupt blood sugar levels and trigger diabetes, researchers said Wednesday in a study that helps explain the link between obesity and a disease typically linked to sugar. Fatty foods can suppress an enzyme crucial to the production of insulin, which regulates sugar in the blood, scientists at UC San Diego said.

How many people participated in the study? None

You guessed it, this wasn't a human study, it was an animal study. In this one, the participants were mice.

The normal diet of a mouse is about 5% fat, 15% protein and 80% carbohydrate - a very different macronutrient (fat, protein, carbohydrate) mix than we humans eat.

Now this isn't to say that animal models are useless or unable to provide useful data - they are and they have for years. The real problem here isn't the mice per se, it's the media jumping up and down to say the data shows a high fat diet is detrimental for humans. Just look at the headline again.

Even the researchers themselves did not go that far!

The article states that:

"In a study of normal mice that were fed a fatty diet, researchers found that the enzyme was repressed, leaving pancreatic cells unable to sense sugar levels and leading to diabetes.

"Our findings suggest that the current human epidemic in Type 2 diabetes may be a result of GnT-4a enzyme deficiency," said Marth, adding that people who inherit a faulty gene may also be vulnerable to diabetes.

It may also play a role in the early onset of Type 2 diabetes in children and teenagers, according to the study, which was also sponsored by the National Institutes of Health."

I've bolded the important words above. "May" is not "definitive," nor is "suggest" saying that the findings are "definitive."

Hey, if nothing else, we know if we feed mice a diet that is high in fat, they'll have problems. But, does the same hold true for humans?

Quite frankly, it depends on the context - the mix - of the diet one is eating.

If you're eating a large amount of carbohydrates along with a large amount of fat, I'd be the first to tell you you're heading for metabolic nightmares - this "opinion" is even supported by data. Just as the research data shows that if you reduce the carbohydrate and consume higher amounts of fat, well - metabolic disorders in humans tend to reverse - is also an "opinion" supported by data.

And here is where I feel researchers are "missing the boat" when it comes to nutrition studies - they're still focused on macronutrient ratios and too focused on fat in the diet as a percentage of calories.

As I've pointed out before, if you're eating 3,000 calories a day and trying to stay within 30% of those calories from fat, you'll be eating about 100g of fat each day. Now let's pretend you're overweight and need to lose 50-pounds, so you reduce your calories to 2,400 calories a day.

Up until that calorie reduction you've eaten 100g of fat each day, within the "healthy" diet recommendations. If you decide to reduce your carbohydrate instead of your fat and continue to eat 100g of fat each day, the "experts" will now insist you're eating unhealthy, even if reducing your carbohydrate means you're increasing your intake of fresh vegetables while eliminating refined sugars and grains!

Their reasoning is that you've somehow "increased" your fat intake because you're now eating 37.5% of your calories from fat instead of less than 30%.

It doesn't matter that the glucose burden in your body has been reduced, thus reducing your insulin, by eliminating 150g of carbohydrate each day as your source of calorie reduction. Nope, you're now eating too much fat....even though you've now reduced your calories and reduced your body's need to shuttle sugar around and store it when it's in excess amounts.

If the arguement is that calories in calories out are at the heart of weight loss, why then this obsession with dietary fat? Why not offer those who are overweight or obese - or even pre-diabetic or diabetic - an option of what macronutrient they find easier to reduce to reduce calories each day?

For those who are pre-diabetic or diabetic (type II specifically) the research shows that reducing carbohydrate is effective - not only for weight loss, but for improving insulin sensitivity, reducing fasting blood glucose levels, reducing LDL (bad) cholesterol, increasing HDL (good) cholesterol, reducing triglyerides and providing a greater feeling of satiety when followed correctly.

Data - from studies specifically on humans - show that higher percentages of dietary fat & protein with a lower percentage of carbohydrate calories offers many diabetics and pre-diabetics the ability to lose weight and reduce the features of their metabolic disorders. Yet we remain stuck in this thinking that one must reduce dietary fat to lose weight or to improve their health!

As I wrote about just a few days ago in Diabetics, Take Notice! Researchers conclude Low-Carb Diet is an Effective Treatment with 22-Month Data, we're now seeing longer-term human data and it is showing promise that low-carb diets are an effective dietary therapy for diabetes.

Which begs the question - if you're diabetic, which would you rather trust - human data or animal models in trying to determine the best course of treatment, with diet, while working with your doctor to monitor your progress?

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