Vol.
12, Issue 1
by Dean Ornish, M.D., Founder and President, The Preventive Medicine Research Institute, Sausalito, California; Clinical Professor of Medicine, University of California, San Francisco
Drs. Atkins and Ornish square off on weight loss.
If Truth Be Told
In recent years, there has been a resurgence of interest in low-carbohydrate, high-fat diets such as the Atkins diet. The media have added to the confusion, reporting that, “The percentage of calories from fat in the American diet is lower than ever, yet Americans are more overweight than ever, and so, dietary fat is not responsible for obesity.” In fact, per capita consumption of fat has risen by 10 pounds/year since 1975, whereas per capita consumption of simple carbohydrates has increased even more – by 20 pounds/year. So, while the percentage of calories from fat has decreased, the amount of fat consumed has actually increased.
Less Is More
Despite the plethora of diets, losing weight is no mystery: Burn more calories and/or eat fewer calories. It’s that simple.
You can burn more calories by exercising. You can eat fewer calories by consuming less food.
While you can lose weight on any diet that restricts portion sizes, it’s often hard to keep it off because you may feel hungry and deprived. An easier way to lower caloric intake is to eat less fat, because fat (whether saturated, monosaturated or unsaturated) has nine calories/gram, whereas protein and carbohydrates have only four. A 2001 Pennsylvania State University study, for example, found that healthy women instinctively ate about three pounds of food a day, whether high or low in calories. The primary drive was volume, not calories. Thus, by eating less fat, individuals can cut calories by reducing energy density without sacrificing volume, meaning they can lose weight without feeling hungry or deprived.
Simple Isn’t Always Better
The other reason people get too many calories is that they consume too many simple carbohydrates. In my numerous debates with Dr. Atkins, we agreed that many Americans eat excessive amounts of processed foods high in simple carbohydrates, including sugar, high fructose corn syrup, white flour, white rice and alcohol. Because these foods are low in fiber, large quantities of calories can be consumed without feeling full. Also, these low-fiber foods are absorbed quickly, causing blood sugar to spike, which in turn causes insulin to surge. Excess insulin accelerates the conversion of calories into fat. Insulin surges also promote atherosclerosis, contribute to hypoglycemia and hypertriglyceridemia, and over time, in some people, may lead to insulin resistance and even diabetes.
Although we agreed on the diagnosis — that many Americans eat too many simple carbohydrates — we disagreed about the prescription. Dr. Atkins advocated substituting simple carbohydrates with high-fat, high animal-protein foods such as bacon, sausage, butter, steak, pork rinds and brie. I would love to be able to tell you that these are healthy foods, but they are not. Telling people what they want to believe is part of the reason that the Atkins diet has become so popular.
A more healthful choice is to substitute simple carbohydrates, which have a high glycemic (or sugar) load, with complex (unrefined) carbohydrates, including whole foods such as fruits, vegetables, legumes (including soy products) and whole grains (such as brown rice and whole-wheat flour), which have a lower glycemic load. Complex carbohydrates are high in fiber, which enhances satiety without adding significant calories. Also, fiber slows the absorption of food, thereby preventing blood glucose from rising too rapidly and reducing insulin surges.
Complex carbohydrates and whole foods are also rich in phytochemicals, bioflavinoids, carotenoids, retinols and other substances that may reduce the risk of many chronic diseases. In addition, they are low in cholesterol, saturated fat, oxidants and other disease-promoting substances. In contrast, an Atkins diet is high in disease-promoting substances and low in protective ones. Moreover, body weight is inversely associated with dietary fiber and carbohydrate, and positively associated with protein intake. Meat has virtually no dietary fiber.
When people go on a high-protein diet, they may lose weight and lower triglycerides if, like most Americans, they had been eating a diet high in simple carbohydrates. Even better would be to reduce the intake of simple carbohydrates and most fats, which results in losing even more weight while enhancing health rather than potentially harming it.
Why Some Studies Claim an Atkins Diet Is Better Than a “Low-fat” Diet
While short-term studies show that an Atkins diet does not raise LDL, or bad, cholesterol very much, a five-year follow-up of the Lifestyle Heart Trial conducted in 1998 revealed a diet containing 10 percent of calories from fat with little saturated fat and dietary cholesterol (the diet I recommend) actually decreased LDL-cholesterol (LDL-C) by an average of 40 percent after one year in ambulatory patients not taking lipid-lowering drugs.
Another study, published in 2002 by R.M. Fleming in the peer-reviewed journal Preventive Cardiology, compared 100 people randomly assigned to follow an Atkins diet; a 30 percent-fat diet; a 15 percent-fat calorie-controlled diet; or a 10 percent-fat whole-foods diet with an emphasis on complex carbohydrates. Weight loss was highest (one pound/week) on the 10 percent-fat diet, followed by 0.6 pound/week on the Atkins diet. After one year, there was a 52 percent decrease in LDL-C on the 10 percent-fat diet, whereas there was a 6 percent increase in LDL-C on the Atkins diet. Only patients following the Atkins diet showed a worsening of each cardiovascular disease risk factor, despite achieving statistically significant weight loss.
Short on Proof, Long on Problems
Dr. Atkins often claimed that his diet can reverse coronary heart disease (CHD), but he and other advocates of similar diets have yet to prove this – and disprove the large amount of data linking the intake of a diet high in animal fat and protein with the incidence of CHD. In fact, studies have shown that CHD patients who followed the diet I recommend – a 10 percent-fat whole-foods diet – demonstrated significant reversal of coronary atherosclerosis after one year (as measured by quantitative coronary arteriography), and even more reversal after five years. Meanwhile, the only peer-reviewed study of the effects of a high-protein, high-fat diet on heart disease found that heart disease became more severe (http://my.webmd.com/content/pages/1/3075_903). Also, high-protein diets may cause loss of calcium and decreased levels of urinary citrate, leading to osteoporosis and kidney stones.
In a 2002 study funded by the Atkins Center for Complementary Medicine, 70 percent of patients on an Atkins diet for six months were constipated, 65 percent had halitosis, 54 percent reported headaches, and 10 percent had hair loss. Since our bodies excrete toxic substances through our bowels, breath and perspiration, these results are not surprising. So Atkins dieters beware: You may lose weight and start to attract people to you, but when they get too close it may be counterproductive!
An Optimal Approach…Not a Prescription
An optimal diet is high in good carbohydrates (complex carbohydrates), good fats (omega-3 fatty acids) and good protein (plant-based), and low in ones that are less healthful. This diet is based predominantly on fruits, vegetables, grains and legumes in their natural, unrefined forms.
In practice, someone trying to lose weight may begin by moderately reducing his/her intake of simple carbohydrates and fat, and moderately increasing his/her level of exercise. This is the premise of organizations such as America on the Move. If moderate changes are not sufficient to achieve the desired goals, then the individual can be encouraged to make more intensive ones. The advantage of small changes is that the barriers to change are low; however, the benefits are also modest. Paradoxically, it may be easier for people to make more comprehensive changes in diet and lifestyle because they experience the benefits so quickly and to a much greater degree.
The concept of a dietary spectrum is to empower with information and freedom of choice rather than to focus on feelings of constraint and restriction. Thus, individuals develop a way of eating, rather than simply following a diet with rigid “eat this” and “don’t eat that” guidelines. For example, someone may indulge one day and eat more healthfully the next. To the degree people reduce their overall intake of simple carbohydrates and excessive fat, and increase their intake of whole foods such as complex carbohydrates, they are likely to lose weight – and gain health. {
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