Tag Archives: Johns Hopkins

Low Carb Poses No Arterial Health Risks

Will a Low-carb, High-fat Diet Clog Your Arteries?

The evidence against dietary fat has always been flimsy, and based mainly on studies more suited to developing a hypothesis than coming to a conclusion. Now evidence is mounting that much of what we have heard is wrong. A report in the Johns Hopkins University Gazette states:

Overweight and obese people looking to drop some pounds and considering one of the popular low-carbohydrate diets, along with moderate exercise, need not worry that the higher proportion of fat in such a program compared to a low-fat, high-carb diet may harm their arteries, suggests a pair of new studies by heart and vascular researchers at Johns Hopkins.

“Overweight and obese people appear to really have options when choosing a weight-loss program, including a low-carb diet, and even if it means eating more fat,” said the studies’ lead investigator, exercise physiologist Kerry Stewart.

Johns Hopkins and Low Carb Diets

Johns Hopkins has been at the forefront of research into various low carb diets, and has been successful in treating various conditions with a low carb, high fat ketogenic diet. They have found them safe in their studies of children with seizure disorder.

Low Carb Age first reported on the new study in our June report on the growing mass media acceptance of low carb diets.

The researchers stress that the direct comparison of a low carb and low fat diet in this study included moderate exercise for both groups. Like many modern press accounts conceding that a low carb diet works, the authors stress the efficiency of the low carb diet in losing weight without killing you. Unspoken, but implied, is the suggestion that once you lose the weight you can return to a higher carb diet.

Why Not Abandon Low Carb After Reaching your Weight Goal?

Abandoning the low carb way of eating after reaching your weight goal is a prescription for disaster, causing the familiar American model of yo-yo dieting. A much better approach is to view a low carb, high fat diet as being a permanent change in lifestyle.

That’s already the case for Hollywood stars like Courtney Thorne-Smith and country singers like Dolly Parton. The significance of Courtney and Dolly is that they represent the top two groups of people who biologically have the hardest time losing and then maintaining weight: pre- and post-menopausal women.

Eventually, mass media will recognize the long term benefits of reducing carbs, eating mainly foods you prepare yourself, and avoiding highly process, artificially sweetened frankenfoods.

Mass Media Acceptance

The evidence that the Low Carb Age is upon us keeps amassing, albeit with the usual caveats to assuage guilt. As the authors of Mistakes Were Made (But Not by Me) tell us, people in positions of authority rarely admit they were wrong.

Nevertheless, the truth begins to squeak out. This week the NY Times’ Tara Parker-Pope’s Phys Ed column reports on a significant new study from Johns Hopkins to be published this Friday:

With the memory of Memorial Day cheeseburgers and bratwursts still lingering, many of us may be relieved to hear that a new study suggests that a meaty, high-fat, Atkins-style diet can do more than contribute to rapid weight loss. It may also be less unhealthy for the heart than many scientists had feared — provided you chase the sausage with a brisk walk.

So Close, Yet So Far

Parker-Pope makes the mistake of insisting exercise was proven to be part of the solution, but the study shows no such thing. It specifically compares a low fat to a “low carb” diet, both with the same amount of exercise. As The Behavioral Medicine Report explains:

Low-carb dieters showed no harmful vascular changes, but also on average dropped 10 pounds in 45 days, compared to an equal number of study participants randomly assigned to a low-fat diet. The low-fat group, whose diets consisted of no more than 30 percent from fat and 55 percent from carbs, took on average nearly a month longer, or 70 days, to lose the same amount of weight.

Both groups had an exercise component. In the absence of a correlating study showing that the same diets without exercise has a different outcome, Parker-Pope’s assertion is without any foundation. Pre-conceived notions are hard to shake.

How Low is Low

As we’ve seen in other studies, the term “low carb” used here is inexact. The low carbohydrate group consumed up to 30% of their calories from carbs. Considering this a low carb diet is a bit of a stretch. Most people adhering to a low carb diet to lose weight start with about 40 grams of carbohydrates per day, or 160 calories from carbs. For a healthy man consuming 2,500 calories per day, carbs during Induction on Atkins represent about 7% of calories. That same man on the test diet in this study would be consuming about 185 grams of carbs. That’s higher than many people on a low carb maintenance diet.

This study did reduce calorie content by about 700 calories over the baseline for each individual. Even for a 2,000 calorie diet, the “low carb” dieter is consuming 150 grams of carbs.

Why Calories Don’t Matter

This study provides yet another example why the “calories in / calories out” model is flawed, as the low carb group lost weight 30% faster than the low fat group. They both consumed 700 fewer calories per day than before, but the low carb group lost weight faster. If the body reacts to all food the same way, as a strict “calories in / calories out” model suggests, then both groups would have lost weight at the same rate. But in study after study, we find that the low carb group loses weight faster and with less hunger than the low fat group. What you eat matters as much as how much you eat.

The Original Purpose

The trial was designed to test the differences in vascular function for people on both diets, and both showed no change. It is the first study to actually test vascular function among a group of people. That is good news for people considering a low carb diet. As lead investigator exercise physiologist Kerry Stewart, Ed.D, says:

“Our study should help allay the concerns that many people who need to lose weight have about choosing a low-carb diet instead of a low-fat one, and provide re-assurance that both types of diet are effective at weight loss and that a low-carb approach does not seem to pose any immediate risk to vascular health,” says Stewart. “More people should be considering a low-carb diet as a good option,” he adds.

The study is due to be published Friday, June 3.

Hopkins: Ketogenic Diets Safe

Johns Hopkins has been doing research and clinical trials on ketogenic diets for seizure disorders in children for years. The diet they use is much more carb-restricted than we find in PP, and probably higher in fat content. The article in Diabetes in Control describes it this way:

The ketogenic diet, consisting of high-fat foods and very few carbohydrates, is believed to trigger biochemical changes that eliminate seizure-causing short circuits in the brain’s signaling system. Used as first-line therapy for infantile spasms and in children whose seizures cannot be controlled with drugs, the diet is highly effective but complicated and sometimes difficult to maintain. It can temporarily raise cholesterol, impair growth and, in rare cases, lead to kidney stones, among other side effects.

The Hopkins Children’s Hospital used the diet for 16 months to 8 years to reduce or eliminate the seizures. The study being referenced is a follow-up to see if any lasting health problems from the diet are revealed.

There don’t seem to be any long-term effects:

Only two of the 101 patients reported kidney stones after stopping the diet, the same rate found in the general population not treated with the ketogenic diet, the researchers say.

None of the 25 patients who had liver and kidney function tests had abnormal results. Among the 26 patients who had their cholesterol tested, the average level was 157 milligrams per deciliter of blood (less than 200 is considered normal), with three of the 26 having abnormal levels. Most patients’ cholesterol levels go up while on the diet, but are believed to return to normal thereafter. The Hopkins study now confirms that this is the case.

In 2008, Johns Hopkins Children’s Hospital described the results on cholesterol this way:

While most children developed high cholesterol after starting the diet, in half of them, cholesterol gradually improved returning to normal or near-normal levels, with or without modifications to their diet to reduce fat intake.

Interestingly, efforts to reduce saturated fat saw no greater decrease in cholesterol levels. In other words, doing nothing and reducing saturated fat had the same effect over time. That might be good news for low carbers that are worried about an increase in cholesterol in the early years of the new way of eating.

Since 2005, Hopkins has noted that a modified Atkins low carb diet plan has nearly the same benefits as their more restrictive ketogenic diet for children with seizure disorders. In effect, any diet that puts the patient into ketosis restricts the seizure activity.