Tag Archives: low fat vs low carb

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.

RD Turn-About: Fat Not So Bad

The American Dietetic Association is a low fat bastion, with member dietitians rarely advising patients to embrace a low-carb lifestyle. Doctors routinely refer their patients to Registered Dietitians for guidance, and their advice is normally horrendous. So it was with great interest that I read the news item regarding a presentation at the American Dietetic Association’s (ADA) Food and Nutrition Conference and Expo this month (November, 2010). From a news story in Food Navigator USA:

During a symposium called “The Great Fat Debate: Is There Validity In the Age-Old Dietary Guidance?” at the American Dietetic Association’s (ADA) Food and Nutrition Conference and Expo, four leading experts presented evidence suggesting that low fat diets may be less healthy than those containing at least a moderate amount of fat. In particular, all four agreed that replacing saturated fat with carbohydrates – as has been widely recommended in the United States – is likely to raise the risk of cardiovascular disease.

Emphasis mine. Just thought I’d bold that statement in case any deaf Dietitians were in attendance.

It is not that this is “new news”. The evidence has been mounting, and Low Carb Age has been documenting the end of the low fat diet craze for over a year now. But to have the ADA admit it is a very big deal indeed.

Just to recap some stories in the past year:

Dietary intakes of saturated fats are not linked to cardiovascular disease, so says a meta-analysis of 21 studies from across the world.

Data from almost 350,000 subjects obtained from 21 studies indicated that dietary intakes of saturated fat are not associated with increases in the risk of either coronary heart disease (CHD) or cardiovascular disease (CVD), US researchers report in the American Journal of Clinical Nutrition.

“Our meta-analysis showed that there is insufficient evidence from prospective epidemiologic studies to conclude that dietary saturated fat is associated with an increased risk of CHD, stroke, or CVD,” wrote the researchers, led by Dr Ronald Krauss from the Children’s Hospital Oakland Research Institute in California.

Japanese researchers noted an increase in mortality – that means death, folks – from strokes in those that adopted a low fat diet:

Very low intakes of saturated fats may be just as bad for you as very high intakes, and could lead to an increased risk of death from stroke – according to new Japanese research.

The study, published by the American Journal of Clinical Nutrition, suggests that a very low dietary intake of saturated fatty acids (SFA) is associated with an increased risk of stroke.

“SFA [saturated fatty acids – saturated fat] intake was inversely associated with mortality from stroke. This inverse association was similarly observed for intraparenchymal hemorrhage and ischemic stroke,” wrote the researchers.

Some of the stories show the conflicted nature of researchers facing unpleasant results. One study looked at low fat diets and concluded that it was the type of carbohydrates in the diet that were at fault:

People who cut saturated fats while increasing intake of refined carbohydrates like white bread and pasta have a higher risk of heart attack, according to a study published in the American Journal of Clinical Nutrition.

However, the Danish researchers found that reducing saturated fats while increasing intake of non-refined carbohydrates – such as wholegrain bread and vegetables – could improve heart health. A recent meta-analysis published in the same journal earlier this year called into doubt the widely held theory that high saturated fat intake is linked to high rates of heart disease – but the researchers behind that review said that other dietary elements of the 350,000 subjects involved could be more important.

. . .

They found a statistically significant correlation between replacing saturated fat calories with refined carbohydrates – those described as ‘high-GI’ and thought to cause a spike in blood sugar levels – and heart attack risk. For those subjects with the highest average dietary glycemic index, heart attack risk increased by 33 percent for every five percent increase in calorie intake from carbohydrates.

See the disconnect? I have emphasized the pertinent passage. They are still preaching the “whole grain breads” line while simultaneously saying that High Glycemic Index (GI) foods should be avoided. Yet whole grain bread often has a higher GI than plain old white bread (average of 62 vs. 59). You can see the official GI of different foods at http://www.glycemicindex.com/

Not that the gycemic index should really be a guide. For most Americans, cutting out refined carbs, including all breads, cookies, muffins and cakes, would go a long way toward curing the obesity problem in this country. Whole wheat and whole grain breads are still refined carbs, and spike blood sugar. Wheat may be implicated in numerous health issues due to allergies and sensitivities, sometimes hidden behind nebulous diagnoses of Chronic Fatigue Syndrome or PCOS.

Following a true low carb lifestyle, or adopting a paleo outlook to eating, would greatly enhance health while avoiding the hunger that plagues low fat dieters, and may clear up other health issues (as I found with eliminating GERD and insomnia).

Welcome to the club, dietitians!

Twilight Zone of Diet Studies

Imagine if you will a diet study, a seemingly ordinary diet study. One that compares low carb and low fat diets. Now imagine that you are reading the results, and find the unequivocal superiority of the low carb diet.

Results:

Both the Low and Moderate Carbohydrate groups lost significantly more weight as well as inches from their waists and thighs than the Control group, while the Low Carbohydrate group lost a greater percentage of body fat. Although the Moderate Carbohydrate group showed significant reductions in serum cholesterol, the Low Carbohydrate group showed the greatest improvements in serum cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, and very-low-density lipoprotein.

Consider, if you will, how you would write the conclusion to these findings. That all-important snippet of text that will be read by those too busy to read the full synopsis, the snippet that will be picked up in articles and future studies.

Perhaps you will write something that bears some resemblance to the words and phrases in the Conclusion. Something that recognizes the low carb diet as being at least equal in your test for weight loss, yet reducing more body fat than the low fat diet. Consider how you will sum up the findings, that the low carb diet provided significantly better results for cholesterol and triglycerides. But before you put your pen to paper, read the actual conclusion:

Moderate approaches to weight loss such as a moderate-carbohydrate low-fat diet may be prudent.

There is nothing wrong with your eyes. Those are the words the study authors penned. An example, perhaps of cognitive dissonance.

You are traveling through another dimension –a dimension not only of sight and sound but of mind. A journey into a wondrous land whose boundaries are that of imagination. That’s a signpost up ahead: your next stop: the Twilight Zone of Diet Studies!

Low Carb and BP

Dana Carpendar at Hold the Toast blog recaps the results of an interesting study in the Archives of Internal Medicine:

47% of the low carb group had their blood pressure medication discontinued in the course of the study, as compared to 21% of the low fat group. Dr. William Yancy, who ran the study, said the difference in the two groups might have been even greater had subjects remained on their blood pressure medication, but they instead took people off medications as their readings normalized.

The study started the low carb group at the true low carb level promulgated by the Atkins diet, 20 grams per day. Far too often, studies comparing low carb diets to low fat diets use 100 or more grams per day of carbohydrate. The study lasted nearly a year, long enough for true differences in the diets to be seen. For the low fat diet group, the study added a common diet drug, orlistat, a drug that sequesters fat so it can be eliminated before being absorbed by the body.

Weight loss for the two groups is statistically insignificant, even though some low carbers have pointed to the results proudly. The small sample size and small difference in the number of pounds lost between the two groups just doesn’t lend itself to proclaiming any victory for the low carb diet. But the study does show the low carb diet is the equal of a low fat diet in nearly every respect. The study’s Abstract points this out.

No matter what you read, the main benefit of a low carb diet in this study was that it matched the low fat diet in nearly all areas, and was superior in controlling high blood pressure:

Conclusion: In a sample of medical outpatients, an LCKD [low carb ketogenic diet] led to similar improvements as O + LFD [orlistat plus low fat diet] for weight, serum lipid, and glycemic parameters and was more effective for lowering blood pressure.

It would be interesting to see how the participants felt about their low carb or low fat diet. My experience has been that the low carb diet is much easier to maintain, as I rarely struggle with hunger even while losing weight.

And, I love bacon.

American Heart Assoc & Low Carb

The American Heart Association is now recommending a lower carb diet for prevention of cardiovascular heart disease, heralding the beginning of the Low Carb Age!

A new study, recently presented at the American Heart Association annual meeting in Orlando, FL, tested the effect of a low fat verses moderate fat diet. The low fat diet contained 20 percent of calories from fat, 65 percent from carbs and 15 percent from protein (this is the standard low fat diet that has been recommended for years). The “moderate fat diet” increases fat, and to keep the calories consistent, lowers the carbohydrate contribution. The moderate fat diet in the study has 40 percent of the calories from fat, 45 percent from carbohydrate and 15 percent protein. HealthDay, from the National Institutes of Health, quotes the AHA:

“This is a good study that essentially confirms that the current recommendations are appropriate,” said Alice Lichtenstein, a spokeswoman for the American Heart Association (AHA). “Since 2000, the AHA has been recommending not a low-fat diet, but one that is low in saturated fats and trans fatty acids.”

People with metabolic syndrome are glucose-intolerant, meaning they can’t process blood sugar well. Low-fat, high-carbohydrate diets exacerbate this condition, Lichtenstein explained.

The study is explained in more detail on our Diabetes and Metabolic Syndrome research page. The conclusion of the study gives the bottom line:

Conclusions: This is the first study to examine the effects of low fat vs. moderate fat diet in MetS. MF compared to LF diet improves the atherogenic dyslipidemia of MetS. MF diet is a preferable dietary intervention in people with MetS to improve CVD risk.

Whew. What the heck does that mean? Here’s a layman’s plain English translation:

This is the first study to examine the effects of low fat vs. a moderate fat diet with lower carbohydrates in patients with metabolic syndrome. The moderate fat diet compared to the low fat diet improves the heart disease related risks of various blood fats (VLDL, LDL, triglycerides, etc.) in people with metabolic syndrome. The moderate fat diet is therefore a better diet for people with metabolic syndrome.

Health Day goes on to quote other experts:

Experts familiar with the study aren’t surprised by the findings. “This sort of falls within the boundaries of what we used to call the Atkins diet, which was a high-lipid and low-carb diet. Normally this kind of diet suppresses appetite, improves diabetes,” said Dr. Alfred Bove, president of the American College of Cardiology. “This diet looks like it does a good job of altering the negative metabolic effects of early diabetes or high carbohydrate stimulation,” he said.

“Much of this we’ve known before, but the idea is that a moderate-fat diet is something most people can tolerate,” Bove said. “It probably affects the way insulin is released because if you have a lot of carbohydrates in the diet, you tend to generate a lot of insulin, and insulin is the hormone that lowers blood sugar,” Bove explained. “In addition to lowering blood sugar, it also increases appetite so a lot of people on high-carb diets are restimulated to eat more.”