- What's wrong with low-carb?
- Vitamin and mineral deficiencies, with increased risk of cancer and heart disease
- Serious side effects
- Not effective, not sustainable, not healthy
What's wrong with low-carb?
"The Atkins diet is anything but health-promoting."
This was said by Robert Eckel of the University of Colorado's Center for Human Nutrition in Denver, who is concerned that people following the Atkins diet, or similar plans, won't eat the wide range of fruits, vegetables and whole grains that is almost universally held to be beneficial.
Read on.
Diets are now very popular. It's not surprising, since the percentage of the population who is classified from overweight to obese is already large and still increasing in Western countries.
The appeal of diets, or at least quick fix diets, is that they appear to be some kind of easy way out. Rather than working out how to change some of your deep-rooted habits, something which has now become part of your life, you have somebody else do all the thinking for you, and you just have to follow a series of pre-ordained steps: 1, 2, 3... Or so it seems.
Many kinds of diets are experiencing a boom, but especially the quick fix diets, the ones that promise people to help lose their weight without much effort, or even actually indulging in the foods they like.
A diet of this type is the one proposed by Dr. Robert Atkins, the best-selling author of Age-Defying Diet Revolution and Diet Revolution.
His theory is that, guess what, a high-protein low-carbohydrate nutrition is beneficial. This idea actually turns the principles of the healthy-eating pyramid (with lots of carbohydrates, a little protein and minimum fat) on their head. He also adds a series of vita-super nutrients to his nutrition plan.
A multibillion-dollar industry hangs on these claims.
It's not hard to see why this diet is so popular, particularly in the USA. The so-called Low-Carb Diet encourages people to do what they would like to do, without even having to feel guilty for it. Another variation in this "low-carb diet" current fad is The South Beach Diet.
In fact, the general medical community is unfavorable to the Atkins Diet, which has been condemned by major health authorities as a highly dangerous cocktail of all the worst possible nutritional advice.
Many leading medical and health organizations, including the American Medical Association, American Dietetic Association (ADA), the American Heart Association, and the American Diabetes Association oppose it.
This high protein low carb diet has been rejected by major medical and nutrition experts and associations, including the U.S. government in its many manifestations (FDA, Department of Agriculture, NIH, et al.), and has been deemed especially dangerous for women, as it depletes the body's calcium stores.
The American Heart Association, the American Dietetic Association, and the American Kidney Fund have all published statements warning about the various dangers associated with low-carbohydrate high-protein diets.
Similarly, the American Cancer Society says high protein low carb diets "can be a high-risk option".
In the UK, over 97% of state-registered dieticians recently surveyed condemned the Atkins Diet, saying that it gave "bad dietary advice". Dieticians warn that this diet could actually impede weight loss in the long-term.
A concern has been expressed that many people have admitted to following celebrity-endorsed diets, which are popular with the film stars and frequently reported in the media, such as The Atkins Diet.
UK dieticians say that the diet should, but does not, advise people to seek medical advice before trying it. And they say that the Atkins diet contradicts all government advice to maintain a healthy and well balanced diet.
Vitamin and mineral deficiencies, with increased risk of cancer and heart disease
There have been no significant long-term scientific studies on the Atkins Diet. It departs drastically from the dietary intakes recommended by the U.S. Department of Agriculture and the National Institutes of Health.
The Atkins Diet is the direct opposite of the food pyramid that the American Dietetics Association, the American Academy of Pediatrics, the National Institutes of Health, and the American Cancer Society all implore you to follow for the sake of your health. It also skips most of the foods that naturally contain important nutrients like antioxidant vitamins.
Much of the opposition is because the diet is lacking in some vitamins and nutrients, and because it is high in fat. In a hearing before the U.S. Congress on February 24, 2000, an American Dietetics Association representative called the Atkins diet "hazardous" and said it lacked scientific credibility.
Adherence to the Atkins diet can result in vitamin and mineral deficiencies.
The Atkins diet and similar ones that promote a high intake of animal protein are also being blamed by medical authorities for putting subscribers at risk of developing a host of life-threatening conditions, including heart disease and stroke.
The Journal of the American Medical Association, the leading American medical publication, has recently published the results of a 20-year study of more than 148,000 adults aged 50 to 74: it found that those with the highest consumption of red meats were 50 percent more likely to develop cancer in the lower colon than those with the lowest consumption. This is consistent with a Harvard research showing that Atkins-type diets are linked to a three-fold increased risk of colon cancer.
Eating a lot of red meat and processed meats such as salami and pastrami over a long period of time poses a colon cancer risk.
Those are numbers and percentages that could be important to the followers of the Atkins diet, which encourages consumption of meats, said Dr. Michael J. Thun, head of epidemiological research at the American Cancer Society.
"The Atkins diet became popular just recently, so no one knows the health effects long-term," he said. "But the accumulating evidence that a diet high in red meat or processed meat increases the risk of colon cancer indicates that it would certainly be undesirable to remain on the Atkins diet long-term."
Another result comes from the magazine of Oxford University students:
"A group of Oxford scientists have subjected themselves to the controversial Atkins diet, with a number suffering ill health as a result.
"The researchers found that the diet caused them to experience a fast and irregular heartbeat - a condition that can lead to heart failure in the long term.
"In the most extreme cases, it took participants two months to overcome the effects.
"The group of 17 researchers from the Physiology and Cardiology departments spent two weeks observing the effects of the diet, in which participants avoid carbohydrates in favour of protein rich foods such as meat, eggs and cheese.
"Dr Sheuermann-Freestone, who was leading the research, stressed the provisional nature of the findings, but commented that she would 'most certainly not' recommend anyone to follow the Atkins diet, despite the fact that participants did lose between two kilograms and five kilograms during the experiment.
"'The weight will be lost in a most unhealthy way with lots of possible side and long-term effects. It is much better to cut down a little on the carbohydrates, a lot on the fats, and exercise in parallel.'
"The study was conducted in conjunction with the British Heart Foundation in the hope of better understanding how free-fatty acids, which surround the heart, actually function.
"It is hoped that the results can be used in developing new treatments for diabetes and heart conditions.
"Despite widespread criticsm, 'Dr Atkins' New Diet Revolution', made famous by its large celebrity following, has now sold over six million copies, becoming one of the most popular fad diets of all time."
A study published in the American Journal of Kidney Diseases shows that high-protein, low-carbohydrate diets cause rapid and pronounced loss of calcium in the urine, which can lead to osteoporosis, while studies of vegetarian diets have shown safe, effective weight loss. Studies published in the Journal of the American Medical Association show that a low-fat vegetarian diet can reverse heart disease.
Serious side effects
According to Atkins, the diet causes no adverse side effects. Many health care professionals disagree. In a fact sheet for the Healthcare Reality Check website, registered dietician and author Ellen Coleman said the diet may have serious side effects, among which ketosis, dehydration, electrolyte loss, calcium depletion, weakness, nausea, and kidney problems. "It is certainly riskier for overweight individuals with medical problems such as heart disease, hypertension, kidney disease, and diabetes than it is for overweight people with no health problems," she said.
Diabetics taking insulin risk becoming hypoglycemic if they do not eat enough carbohydrates. And people exercising regularly may have low energy levels and muscle fatigue because of low carbohydrate intake.
Research conducted at the University of Texas found that Atkins-type diets also increase the risk for kidney stones. An unpublished study funded by Atkins himself found that the people in the study who were on his diet experienced everything from constipation to headaches to hair loss to bad breath.
Not effective, not sustainable, not healthy
The initial rapid weight loss in Atkins diets is only due to water loss.
Popular diet books point out that cutting out carbohydrate-containing foods may lead to temporary weight loss. This fact has been misinterpreted as suggesting that carbohydrate-rich foods are the cause of obesity. In epidemiological studies and clinical trials, the reverse has been shown to be true. Many people throughout Asia consume large amounts of carbohydrate in the form of rice, noodles, and vegetables and generally have lower body weights than Americans, including Asian Americans, who eat large amounts of meat, dairy products, and fried foods. Similarly, vegetarians, who generally follow diets rich in carbohydrates, typically have significantly lower body weights than omnivores.
Dena Bravata, a physician at Stanford University in California, and her twin sister Dawn at Yale University, with other colleagues, began scouring the scientific literature as far back as 1966 for papers addressing the efficacy and safety of low-carbohydrate diets. The results of this systematic review should give the followers of the Atkins craze food for thought. They couldn't find any evidence that diets containing low proportions of carbohydrates were more effective. Consuming fewer calories overall, and sticking with a diet for a long time, were the only significant factors for slimming success.
The survey also revealed how painfully thin the science of dieting is. Searching for relevant terms on literature databases turned up a total of 2,609 articles. But just 94 of the studies met the researchers' criteria for inclusion in their review, such as using proper controls and lasting longer than four days. In few cases were there sufficient data to assess the safety of the diets. Information on exercise was rarely reported, making it impossible to compare diets in sedentary and active patients. Few studies looked at different ethnic groups, only five lasted longer than 90 days, and not many included participants over 60 years old. If you are planning to diet in later life, there is little evidence to go on.
"Faddy diets are increasing in popularity but are only temporary solutions," says Amanda Wynne, a registered dietician and spokesperson for the British Dietetic Association. "You lose weight on any restrictive diet. On a cabbage soup diet you cut down on your calories and lose weight, but it's not sustainable. When you go back to your old eating habits you put on weight again."
The other concern is that most faddy diets cut out whole food groups. Wynne says: "The Atkins diet cuts out many fruit, vegetables and carbohydrates and these are important sources of vitamins, minerals, antioxidants and fibre. These elements of diet are associated with reductions in heart disease and cancer."
The rationale behind the Atkins and South Beach diets is that there's a metabolic advantage in manipulating the intake of fats and carbohydrates. "They claim that if you eat lots of fat you burn up fat more easily," says Wynne. "But the bottom line is that the number of calories you eat determines how much weight you lose. There is no evidence that you will lose fat preferentially if you eat more fat."
Many people on these diets restrict their calories, at least initially, to 1,000 calories or fewer a day. This rapidly burns stores of carbohydrates in the body, which then turns to using up fat to provide fuel. "This isn't a desirable metabolic state," warns Wynne. "By severely restricting your calories you go into a condition called ketosis. You are starving yourself and you will feel weak, nauseous and have bad breath. If you talk to people on these diets you find they've eaten next to nothing during the day - one chicken drumstick and half an apple. Weight will drop off but they will put it on again."
Research in the New England Journal of Medicine supports this. A study saw 63 obese men and women randomly allocated to either an Atkins type diet (low carbohydrate, high protein and fat) or a low calorie, high carbohydrate, low fat (conventional) diet. At three months the Atkins group had lost an average 4 per cent more, but after a year this difference had gone. The overall weight loss was only 4 kg, and more than a third of people dropped out of the study. Dr Robert Bonow and Dr Robert Eckel, from Northwestern University in Denver, commenting on the study in the NEJM, warned that a diet high in saturated fat increases cholesterol levels and the risk of heart disease.
Dr Jules Hirsch of the Rockefeller University in New York was not surprised. "The impact this diet has had on obesity is virtually nil and this data shows there is no reason to follow this diet. There is immense public interest in restrictive carbohydrate diets but it is based on hearsay. There is a great paucity of scientific evidence."
There is no scientific evidence, agrees Wynne, that any manipulation of food makes us lose weight - unless we reduce calories. "Food-combining diets say you shouldn't eat protein and carbohydrate together because the body can't digest both and so you store food as fat," says Wynne. "But people lose weight initially because it is so difficult to follow the dietary rules that they haven't got time to eat as many calories."
The American Institute for Cancer Research says that food-combining diets such as the New Beverly Hills Diet tout theories "about the mechanics of digestion that are scientifically incorrect".
Barry Groves, a lecturer in Dietetics and Obesity and author, believes that diets such as Atkins appeal to women because they cause initial rapid weight loss. "The first two weeks they can only eat 20g of carbohydrate a day - around one-and-a-half slices of bread - so they lose weight quickly," he says. "But there is a survival advantage in storing fat - in the past those who survived had fat stored for the hard times, so our metabolism slows down if you lose fat too quickly and your weight loss levels out while you may still be overweight. It's called stalling. The body gets frightened, so you need to lose weight more slowly."
The Physicians Committee for Responsible Medicine, finally, has been speaking out about the dangers of high-protein diets since its founding in 1985. Studies show that meat-heavy, high-protein eating patterns are, over the long run, linked to osteoporosis, heart disease, colon cancer, and renal disease, and pose particular dangers for people with diabetes.
These health risks are serious, and the scientific evidence currently available is strong.
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