High-Carb Diet Raises Insulin Levels Which Spikes Blood Pressure, Research Reveals

In the infamous Stanford JAMA study released in March 2007, researchers found the Atkins low-carb diet was most effective not just for weight loss, but also improvements in certain health markers--including reducing blood pressure.

Now this Reuters story about a new study confirms that a high-carb, low-fat diet indeed leads to an increase in blood pressure. The reason why will astound you!

Lead researcher Dr. Meena Shah, associate professor of clinical nutrition at the Dallas, TX-based University of Texas Southwestern Medical Center, and her team of researchers wanted to see if the highly-touted high-carb, low-fat Dietary Approaches to Stop Hypertension (DASH) diet was the best way to treat high blood pressure.

Dr. Shah used a meta-analysis of ten intervention studies (6 randomized crossover, 1 randomized parallel, and 3 non-randomized) comparing a high-carb, low-fat diet with a low-carb, high-monounsaturated fat diet to see what impact these differences in macronutrients would have on the blood pressure. They took great pains to insure the studies they observed had participants whose weight remained stable.

What did the researchers find?

Using a random-effects model, the high-carb, low-fat diets caused "significantly higher" systolic blood pressure and diastolic blood pressure than the low-carb, high-monounsaturated fat diets did. Even when the meta-analysis included just the randomized crossover studies, the results were similar although not as pronounced.

Despite these clear differences in blood pressure between a high-carb, low-fat diet and a low-carb, high-fat diet, Dr. Shah and her researchers just could bring themselves to push for changes in the DASH diet to include less carbohydrate.

"Diets rich in carbohydrate may be associated with slightly higher blood pressure than diets rich in monounsaturated fat," the researchers concluded. "However, the magnitude of the difference may not justify making recommendations to alter the carbohydrate and monounsaturated fat content of the diet to manage blood pressure."

Well, why the heck not?! Isn't the evidence staring you right in the face? You can bet if the low-carb diet was the one raising blood pressure that this would have been on the front page of every health publication around the world declaring how unhealthy this "extreme" and "dangerous" diet is. But this is the fully-embraced low-fat diet we're talking about here and they've got to protect it from being harmed.

The results of this study appeared in the May 2007 issue of the American Journal of Clinical Nutrition.

This isn't the first time Dr. Shah has published research on the impact of a high-carb diet on blood pressure. In 2005, she had a 6-week study published in the journal Diabetes Care which observed 42 Type 2 diabetics placed on either a high-carb, low-fat diet or a high-fat moderate-carb diet to see how it would impact their blood pressure.

Guess what? Blood pressure went WAY up on the high-carb, low-fat diet. Dr. Shah concluded at the time that "long-term consumption of a high-carbohydrate diet may modestly raise blood pressure in type 2 diabetic patients."

Hmmm, so the longer the exposure to a high-carb diet, the more likely that person eating such a diet will be exposed to what is commonly described as "the silent killer" known as hypertension, or high blood pressure.

Here are two damning studies against consuming the recommended high-carb, low-fat diet for blood pressure conducted by the same researcher and yet she still doesn't believe changes in the recommendations need to be made. What's wrong with this picture?

Aren't these people scientists, who based their decisions on what the data shows them over and over again? It would make perfect sense to conclude based on the evidence that eating carbohydrate in the diet in the excessive amounts that are promoted as healthy is a crazy way to try to lower your blood pressure. It's NOT gonna happen!

Dr. Shah even acknowledges the reason why blood pressure goes up in people who eat a high-carb diet is because of raised insulin levels, aka hyperinsulinemia (something low-carb researcher Dr. Jeff Volek from the University of Connecticut acknowledged as the root cause of obesity, diabetes, and other health complications at the recent American Society of Bariatric Physicians obesity conference I attended in Nashville, Tennessee).

The working theory behind increased insulin levels and blood pressure is that hyperinsulinemia strikes a chord in the central nervous system which then in turn makes the heart rate rise and other physical reactions which lead to the spike in blood pressure.

In light of this, wouldn't it seem logical to simply avoid a high-carb diet? What's wrong with making a recommendation like this to people rather than telling them to stop eating salt?

Whatever happened to just plain common sense anymore?

Study: High-Carb, Low-Fat Diet Ineffective For People With High Insulin Levels

When I was in Nashville, Tennessee earlier this month for the American Society of Bariatric Physicians obesity conference, there was a presentation made by researcher Dr. Jeff Volek from the University of Connecticut who said we've had it all wrong for years about dealing with obesity.

He said we have long been focused on obesity itself as a problem rather than a symptom which is why the high-carb, low-fat diet has failed to put a dent in the rising rates of people who are overweight and obese. Instead, Dr. Volek said the primary focus should be on dealing with hyperinsulinemia (excessive production of insulin) to treat obesity and the resulting illnesses that come from that.

Dr. Volek made a brilliant point and now this MSN Health column points to a brand new study that basically confirms that thesis exactly.

Lead researcher Dr. Cara B. Ebbeling (who I previously blogged about her study on teenagers and sugary drink consumption), assistant professor of Pediatrics at Harvard Medical School and the co-director of obesity research at the Boston, MA-based Children's Hospital, and her research team observed 73 obese adults between the ages of 18-35 for a six-month intervention period followed by one year of follow-up.

The purpose of the study was to look at insulin production in the study participants and how dietary changes would impact it. The researchers basically wanted to know why a low-fat diet works for some, but doesn't necessarily work for everyone.

Dr. Ebbeling said conventional wisdom always had an answer for this.

"The usual explanation is that some people are more motivated than others," she noted.

However, the results of her research found that it goes much deeper than mere willpower and is actually tied to controlling insulin secretion levels with a specific kind of diet (hmmm, I wonder what it could be?).

The study participants were split in half and put on one of two protein-neutral diets with varying fat/protein/carbohydrate ratios:

HIGH-CARB/LOW-FAT DIET--20/25/55
LOWER-CARB/MODERATE-FAT DIET-35/25/40

(I only wish Dr. Ebbeling would have also thrown in a genuinely LOW-CARB/HIGH-FAT DIET along the lines of the Atkins nutritional approach in there for her study to see how a third group eating a 60/25/15 diet would have performed as well as a VERY LOW-CARB/VERY HIGH-FAT DIET with a ratio of 70/25/5 just to see the difference. Why don't these researchers want to see these diets matched up with the higher-carb ones? But I digress!)

The study began by measuring each study participant's insulin levels 30 minutes after being administered 75 grams of glucose and tracked their progress at 6, 12, and 18 months.

So, what were the results?

Interestingly, the difference in weight loss between the two groups was identical, which matches what most studies have found in recent years comparing low-fat to low-carb diets.

But...(here's the kicker!)

Study participants with "above-average insulin levels" actually LOST FIVE TIMES MORE WEIGHT on the LOWER-CARB/MODERATE-FAT DIET after 18 months (12.8 pounds) compared with the HIGH-CARB/LOW-FAT DIET (2.6).

In fact, the body fat percentage comparison was equally impressive--down 2.6 percent vs down .9 percent, respectively. WOW, now that was quite a difference!

It wasn't just good for their weight loss, though. The LOWER-CARB/MODERATE-FAT DIET group also improved their HDL "good" cholesterol as well as lowering triglycerides better than the HIGH-CARB/LOW-FAT DIET group. However, LDL cholesterol improvements were better on the HIGH-CARB/LOW-FAT DIET (something previous research has confirmed time and time again).

The conclusion of the researchers is that people who struggle to lose weight on a traditional low-fat diet may want to start livin' la vida low-carb to better manage their weight and health.

Well, HALLELUJAH! I've been touting that message from day one here at my blog because it has always been my contention that a low-fat diet has monopolized dietary recommendations by our government and the so-called health "experts" for far too long.

Dr. Ebelling's study now adds even more fuel to the fire of my argument that both low-fat and low-carb should be recommended alongside each other as equally healthy ways to deal with obesity and health problems. Why are we still BEGGING for this to happen when the science is clearly showing what has been obvious all along?

The results of Dr. Ebelling's study appear in the May 16, 2007 issue of the Journal of the American Medical Association.

I wonder how many people even realize they may have hyperinsulinemia these days. Most people probably wouldn't have a clue what that means which is why diabetes has become such an epidemic along with obesity.

If we can help people control their insulin production, something livin' la vida low-carb has shown to do time and time again, then perhaps we can reduce obesity and diabetes. But it is going to take a serious movement to move the mountains of complacency that have built up for decades.

I challenge groups like the American Heart Association (AHA) and the American Diabetes Association (ADA) to look at studies like this one and defend their current positions on a healthy diet.

The same goes for the United States Department of Agriculture (USDA) and the Food & Drug Administration (FDA). I suppose you'd like to see people like Jimmy Moore just go away, but you're not getting off that easy. Why don't you have me come up on Capitol Hill before Congress and share what livin' la vida low-carb has done to change my life for the better, hmmm? I'd be there lickety-split!

That is, if you think you can handle the truth!