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Is low-carb best for weight loss?


Is a low-carbohydrate diet best for weight loss? We take a look

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Disillusioned with the supposed effectiveness of low-fat diets and facing ever-climbing rates of obesity and diabetes, many people have been embracing starch-free diets in droves. Though the diet has been mostly associated with weight loss, practitioners and scientists alike are discovering the benefits of low-carbohydrate diets for a number of diseases, from multiple sclerosis to diabetes. Low-carbohydrate diets are nothing new, as they have been advocated by various doctors and thinkers since the 1800s. It is only in recent years, though, that the low-carbohydrate diet has achieved such wide and sustained popularity.

Myths about low-carbohydrate diets abound and this article will deal with several of them. It’s important for readers to know that the low-carbohydrate craze is a true phenomenon, encompassing many writers and many approaches. Though each differs from the other in slight ways, the bottom line is this: to be healthy, most people would benefit from reducing their intake of carbohydrates and increasing their intake of protein and fats. The following is a brief survey of the various approaches to low-carbohydrate nutrition. Despite their critics, low-carbohydrate proponents stand by their nutritional recommendations as healthy and vibrant.

Dr Robert Atkins

The most famous populariser of low-carbohydrate diets has been American medical doctor, Robert Atkins. His book, Dr. Atkins’ Diet Revolution, was first published in 1970 and has sold millions of copies. The latest revision was released in 2002 under the title Dr. Atkins’ New Diet Revolution (Avon Books, 2002). Unlike earlier versions of the book, the latest revision is heavily referenced, thus ending frequent criticisms that his diet theories have no scientific basis.

Atkins’ approach to weight loss is simple: reducing your carbohydrate intake to less than 40 grams a day will induce ketosis/lipolysis in the body, a condition whereby the body breaks down fat instead of glucose for energy, resulting in weight loss. The allowable foods are unlimited amounts of meats, fats, cheeses, non-starchy vegetables, and limited amounts of nuts and low-carbohydrate fruits such as strawberries. Off limits are honey, sugar, breads, grains and all starchy vegetables like potatoes.

If insulin levels remain high due to excessive amounts of carbohydrates in the diet, ketosis/lipolysis cannot occur.

In Atkins’ and other low-carbohydrateers view, excessive amounts of carbohydrates stimulate excessive insulin release by the pancreas. Insulin is the hormone that carries sugars into our cells for use. It is also the fat-storing hormone and excessive levels lead to obesity and a host of other hormonal imbalances, which can in turn lead to a plethora of degenerative diseases. If insulin levels remain high due to excessive amounts of carbohydrates in the diet, ketosis/lipolysis cannot occur. Ketosis/lipolysis, then, is the key to weight loss on the Atkins diet.

Atkins explains: “The Atkins Nutritional Approach stimulates the process of lipolysis [which is] burning your fat for energy. A secondary process of lipolysis is ketosis. Ketosis occurs when you are taking in a low level of carbohydrates from the food you eat … Lipolysis results in the creation of ketones (ketosis), a perfectly normal and natural function of the body.” Ketones can be used as energy by the body, including the brain.

Atkins has always been criticised about ketosis — dieticians claim it is a dangerous state for the body to be in. It’s well known that during starvation the body will enter ketosis and break down fat for energy. Diabetics can also enter ketosis, leading to bodily acidosis, a life-threatening state. The two conditions, however, are not alike, as will be explained later in this article.

Dr Atkins has propounded his philosophy of low-carbohydrate living in other books not related to weight loss, most notably Dr. Atkins’ Age-Defying Diet (St Martin’s Paperbacks, 2001). In this title, he associates lower-carbohydrate diets with improved longevity. In his non-weight-loss approach, Atkins allows more carbohydrates per day (40+g), but still recommends that daily intake should not exceed about 100g or 400 calories.

Atkins has been criticised by establishment nutritionists and some medical doctors for promoting a diet that, because it is high in animal fat and protein, will lead to heart disease and other diseases. Curiously, critics also accuse the diet of not including vegetables — something which is clearly false if you read the recipes included in the books. Criticisms aside, a recent study published in Obes Res. 2001;9(suppl 3):O132 revealed the effectiveness of the Atkins Diet (and, by extension, all low-carbohydrate nutritional approaches) for weight loss, especially in comparison to its polar opposite: the low-fat, high-carbohydrate diet. The study showed that the Atkins Dieters had more weight loss, more adherence to the diet and better blood lipid profiles than the low-fat, high-carbohydrate dieters.

Barry Groves

In the United Kingdom, another low-carbohydrate approach has been espoused by engineer and author Barry Groves, PhD. After struggling with weight loss for many years, Dr Groves stumbled across the book Eat Fat and Grow Slim by Dr Richard Mackarness. He claimed the book changed his life and his figure for good. The book basically advocates an unrestricted-calorie diet for weight loss. Groves started to give talks in 1971 about his experience with slimming on a high-fat diet. In the 1980s he extended these talks to include other diseases and wrote the books Diet and Be Damned and The Calorie Fallacy and in 2000 wrote Eat Fat, Get Thin!

Life Without Bread

Life Without Bread (Keats Publishing, 2000) is mostly based on the clinical experience of Dr Wolfgang Lutz, an Austrian medical doctor who successfully used low-carbohydrate diets for decades on thousands of patients. The results of Lutz’s clinical successes have been published in several European medical journals and he even authored a German version of Life Without Bread (LWB) as far back as 1967 to good response (the book is now in its 6th edition). His work, however, was ignored in English-speaking countries. After many years, with the help of American biochemist Dr Christian Allan, Lutz secured an American publisher and the results of his experience and research are now available to all English-speaking people.

In Lutz and Allan’s definition, the low-carbohydrate diet should include no more than 72g of carbohydrates a day. The rest of the diet should be made up of protein and fat from a range of plant and animal sources. In sharp contrast to other low-carbohydrate books, Allan and Lutz discuss the effectiveness of low-carbohydrate nutrition in treating and preventing several diseases such as cancer, heart disease, diabetes, colitis, Crohn’s disease and obesity.

In their book, Allan and Lutz explain exactly how excessive carbohydrate intake negatively impacts the body’s hormonally controlled metabolic processes. Metabolism is a delicate equilibrium between anabolism (processes that build up and repair) and catabolism (processes that break down). “Too much carbohydrate in the diet disrupts the balancing act between anabolic and catabolic forces because it sends too much insulin into the blood. Since the body will always move to balance anabolic and catabolic reactions, increases in insulin must be dealt with in some way.” That “way” is for the body to reduce its output of other anabolic hormones such as human growth hormone, and increase its output of catabolic hormones such as various corticosteroids. The consequences can be that chronically elevated insulin levels disrupt the entire endocrine system, leading to decreased tissue repair, reduced sexual function, poor immune function and insulin resistance.

The term “insulin resistance” is mentioned frequently in low-carbohydrate literature. It refers to our cells’ inability to respond to insulin. Insulin is the hormone that shuttles glucose into our cells. It can do this by attaching to certain receptors on the cell wall. But when the receptors are full, the insulin/glucose cannot get in, leading to higher blood sugar and insulin levels.

Over time, the elevations lead to hormonal imbalances, which lead to the long-term damages mentioned above. The cell receptors get full by being clogged up with fat — the result of excess carbohydrates in the diet being converted into triglycerides (fat) by the liver. Sometimes, “insulin resistance” and its cluster of associated conditions is referred to as “Syndrome X”. The final chapter of LWB shows how to implement the low-carbohydrate eating plan in various people such as pointing out that older patients need to be eased into the program over a period of time. They point out the possible health hazards of such an approach.

The Optimal Diet

Polish medical doctor Jan Kwasniewski is credited with developing the so-called Optimal Diet, a high animal fat, moderate protein, low-carbohydrate diet. Kwasniewski has authored numerous books in Polish on his research; a cookbook is also available. Two English translations of his books are currently available, the most recent being Homo Optimus (WGP Publishing House, 2002), which contains recipes and the clinical effects of the Optimal Diet on a variety of diseases. The Optimal Diet differs from other low-carbohydrate approaches in that it maintains fairly strict ratios of the macronutrients in its meals. Dr Bogdan Sikorski, a pharmacologist and toxicologist and translator of Homo Optimus, explains the features of the approach:

“In contrast to other low-carbohydrate dietary regimens, this nutritional model dictates the exact proportion between the three main food components, protein, fat and carbohydrate (1:2.5-3(min):0.8, respectively), which has to be achieved on a daily basis in order to obtain claimed health benefits… Most importantly, both fats and proteins should be biochemically as close as possible to those found in the human body, ie they have to be obtained from animal products. They should also contain a full complement of micronutrients, with products such as eggs, fat-rich bone broths, organ meats and pork fat being the most prominent examples.”

Despite the diet’s clinical success, the Optimal Diet and Kwasniewski have been officially condemned by the Polish medical authorities. In his response to the pronouncement, Kwasniewski pointed out the unwillingness of the Polish medical board to even consider his clinical records, something he has been pushing for over the years.

Other voices

Several other medical doctors and nutritionists have made their contributions to the low-carbohydrate movement as well. Endocrinologist Dr Diana Schwarzbein, MD, has authored the best-selling The Schwarzbein Principle (Communications, 1999). Nutritional psychologist Julia Ross, MA, has written her own low-carbohydrate-friendly book The Diet Cure (Penguin Books, 2000).

Ray Audette has authored Neanderthin (Jeremy Tarcher, Inc, 1999) which espouses a lower-carbohydrate diet that excludes all grains, dairy and processed sugars. Audette, once stricken with rheumatoid arthritis, cured himself with the diet. Medical doctors Michael and Mary Eades have authored two books espousing the low-carbohydrate approach, not just for weight loss but for a host of degenerative diseases and a way of living, too. Protein Power (Bantam Books, 1997) and The Protein Power Lifeplan (Bantam Books, 2000) encompass the Eades philosophy and approach. Nutritionists Ann Louise Gittleman (Keats Publishing, Inc, 1999) and Robert Crayhon (M Evans Publishing, 1999) have also made their literary contributions to the low-carbohydrate movement.

Dangers

Despite the clinical and biochemical evidence supporting the use of low-carbohydrate diets, most medical doctors and dieticians feel such diets are dangerous. The specific fears centre around ketosis and the supposed dangers of animal fats and protein.

Ketosis

When used as a weight loss program, low-carbohydrate diets (when carbohydrate intake is less than 40g a day) result in ketosis, a process whereby the body breaks down fat for energy. It’s claimed that this state is harmful and can lead to metabolic acidosis and death. While it’s true that ketosis occurs in people who are starving to death as the body struggles to find fuel sources, starving people and low-carbohydrate people are not in the same situation, as the latter have abundant access to food while the former do not. Diabetics can also enter a state called ketoacidosis, but this condition results from out-of-control blood sugar levels brought on by excessive carbohydrate intake. Again, this situation is not analogous to that of those following a low-carbohydrate diet.

Protein

Protein is a vital nutrient, essential to good health. There are 22 amino acids that combine to form different proteins, and eight of these must come from the foods we eat. Our body uses these amino acids to create muscles, blood, skin, hair, nails and internal organs. Proteins help replace and form new tissue, transport oxygen and nutrients in our blood and cells, regulate the balance of water and acids, and are needed to make antibodies. However it’s debated that excessive consumption of protein, particularly animal protein, can result in heart disease, stroke, osteoporosis and kidney stones.

Heart disease

According to the American Heart Association, as little as 50-60g of protein or 0.36g of protein per pound of bodyweight is enough for most adults. This breaks down to about 10-12 per cent of total calories, with infants, children, pregnant and nursing women requiring more protein. People on low-carbohydrate/high-protein diets can consume up to 34 per cent of their total calories in the form of protein and up to 53 per cent of total calories from fat. Critics of the low-carbohydrate diet claim this type of protein and fat combination is not healthy because animal proteins are high in cholesterol and saturated fat, causing many people on these diets to experience an elevation in their LDL (bad) cholesterol when they remain on this diet for long periods. A high level of LDL cholesterol is the chief culprit in heart disease, particularly heart attack and stroke.

In response, several researchers have shown that saturated fats do not contribute to heart disease. For example, an Indian study published in Brit Hrt J, 29, 895-905 (1967) of over one million male railway workers found that the meat eaters had a heart disease rate eight times less than the vegetarians, who ate much less saturated fat. Also, Swedish medical doctor and chemist Uffe Ravnskov, MD, PhD, has authored The Cholesterol Myths (Trends Publishing, 2000) which exhaustively debunks the belief that saturated fats or cholesterol cause heart disease.

Lipid biochemist Mary Enig, PhD, and her colleagues have also shown that cancer rates correlate more closely with refined vegetable oil and trans-fatty acid intake from foods like margarine and vegetable shortening than with animal fats. An exhaustive review paper by Australian researchers also showed that red meat does not cause cancer. In contrast, some published research indicate refined sugars and excessive carbohydrates as the prime factors in cancer.

Osteoporosis

Critics also claim that eating a lot of animal protein will cause osteoporosis over time. This is because the increase in the amount of protein consumed, especially from meat and dairy products, raises the levels of uric acid and urea in the blood, which are byproducts of protein breakdown and metabolism. The body eliminates this uric acid and urea by pumping lots of water into the kidneys and urinary tract to help it flush out. However, a detrimental side-effect of this diuretic response is the loss of essential minerals, including calcium, which can lead to osteoporosis. Medical evidence shows the body loses an average of 1.75 milligrams of calcium in the urine for every 1g increase in animal protein ingested. Additionally, as calcium and other minerals are leached from our bones, they are deposited in the kidneys and can form painful kidney stones.

Energy

Many believe carbohydrates are necessary to maintain energy levels, but the body can utilise fatty acids for energy as well as convert protein into glucose on an as-needed basis. Research shows, for example, that the heart prefers saturated fatty acids for its energy needs, not carbohydrates. Another myth is that you only need fruits and vegetables to get enough vitamins and minerals each day. The reality is, however, that vitamins like A and D are found only in animal foods and nutritional factors like carnitine and CoQ10 are predominantly found in animal foods as well.

The fat of the land

Despite the pronouncements to the contrary, low-carbohydrate diets can have much to offer beyond weight loss. Before dismissing them as dangerous food fads, you should take a close and unbiased look at the clinical and biochemical research that supports them to see what benefit they could have for you.