Low Carbs: Unjustly Accused?
August 09, 2004
By: Jerry Brainum

Luther Vandross knows a thing or two about rhythm and blues, having won the coveted Grammy award five times. The singer also knows something about dieting, since he admits to having a life-long weight problem. Vandross has lost 100 pounds off his 6 foot, 3 inch fame no less than 13 times, confirming the adage that it's easier to lose fat than keep it off. But his most recent effort at weight-loss has proved the most successful. "I've never been more healthy than I am now," he says. "I wish I was this healthy when I was 25."

So what's his secret? In 1998, Vandross weighed almost 340 pounds. He had high blood pressure and diabetes, and an admitted addiction to food. He decided to try a diet that arouses more controversy than any other method of eating: low carbohydrate, high protein. It worked. The corpulent crooner dropped 120 pounds of melodious but malevolent bodyfat. He cut out all starches, no rice, pasta, or potatoes were allowed.

Vandross has kept his weight off for four years following the low carb plan. His waist dropped from 52 down to a svelte 34. He looks undeniably better, and feels better, too. By dropping his excess weight, Vandross has also likely avoided the inevitable consequences of carrying too much fat, too long. Such bad effects include cardiovascular disease and full-blown diabetes.

Despite his success, many people considered by some as nutrition experts decry Vandross' dieting methods. The high protein, low carb diet continues to arose the ire of many mainstream medical professionals. Such pundits ascribe a litany of problems linked to the low-carb diet. But a closer look at many such critiques exposes them as nothing more than another type of protein: red herring.

The Case Against Low Carbs
Most critics of low-carb diets point out that it's not carbs that make you fat, but rather a combination of too many calories and too little exercise. While no one doubts that calories serve at the primary cornerstone of any weight-loss plan, and calories do count, its not that simple. What's often overlooked are other aspects of dieting, such as appetite control and hormonal mechanisms. In the case of low carbs, all diets in this category, despite the plethora of different names, focus on insulin control.

Insulin is primarily a storage hormone. Secreted by the beta-cells of the pancreas in response to a meal, insulin provides a number of effects all related to nutrient storage. Thus, it helps ferry sugars into cells, its best known function. Many bodybuilders are aware of the anabolic effects of insulin, which involves aiding amino acid uptake into muscle, as well as decreased muscle catabolic or breakdown effects. Insulin, however, also has a dark side: it is the most potent lipogenic (fat-synthesizing) hormone in the body.

Insulin itself doesn't synthesize fat, but it promotes every mechanism in the body that does, such as upgraded fat-cell enzyme activity. Insulin also impedes processes known to mobilize bodyfat. In effect, when insulin is secreted, somewhere the body is synthesizing fat. As such, the basic tenet of low-carb diets involves controlling insulin release by limiting the intake of the macronutrient known to promote the greatest release of insulin: carbohydrates.

Anti-carb advocates say that without excess caloric intake, insulin itself won't make you fat. This is true for about 25% of people, but the other 75% tend to oversecrete insulin in response to a meal. While this effect, known as hyperinsulinism, is most often associated with excess bodyfat, leading to a chicken and egg theory of which came first, the excess insulin or the fat that caused insulin insensitivity, some comparatively lean people may also excrete excess insulin, particularly if they are genetically predisposed to diabetes.

Recent in vitro, or isolated cell studies show that when isolated fat cells are exposed to insulin alone, nothing happens. But add some simple sugar to the mix, and the fat synthesizing machinery of the fat cell soon revs into turbo mode. This doesn't occur with either protein or fat, only carbs.

Another clue involves recent surveys showing that Americans are fatter than ever, despite the continuing emphasis on low-fat foods. Low-carb critics often note that fat, at 9.3 calories per gram is about 2 1/2 times more calorically dense than carbs. That's true. The problem is that people have the mistaken idea that they can eat all the low-fat snacks and foods available today with impunity. But such foods simply substitute carbs for fat, and eat too much of anything and you'll get fat, it's simple physics.

Another frequently voiced charge against low-carb diets involves ketosis. A lack of carbs leads to an increased mobilization of fat for energy purposes. In effect, your body switches from being a sugar-burning machine to a fat-burner. But one effect of increased use of fat as an energy source is that some of the fat isn't completely burned, increasing by-products called ketones, which are metabolic acids. The good news about ketones is that they may help blunt appetite, a definite asset for dieting purposes. Ketones also have a protein-sparing effect, helping you maintain muscle mass while losing fat. Ketones themselves can be used as an alternative source of energy for muscle and other tissues.

Self-styled nutrition experts obfuscate the ketone issue by listing side effects associated with increased ketones under pathological conditions. These include the uncontrolled acidosis linked to poorly treated diabetes. Or the increased ketosis associated with extended fasting or starvation, neither of which apply to low-carb diets. In fact, most pregnant women show the same level of ketosis linked to low-carb diets, with no harm to either the mother or developing baby.

The one truth about low-carb ketosis is that it is involved in raising the Ph or acid levels of the blood. This can cause some potentially serious problems, but it can easily be dealt with as discussed later. The point here is that for most low-carb dieters, the worst thing about the mild ketosis they may experience is a type of acetone breath caused by expelled ketones in the breath.

Low carb diets are considered bad because they are high in protein. Some experts apparently ignorant of recent research are not aware that protein itself is a potent appetite suppressant. Other studies show that the alleged bad effects of a higher protein intake, such as calcium loss and kidney disease, aren't applicable to healthy people.

In fact, a high protein intake is one of the "secrets" of why the low-carb diet works for so many people. When you reduce either calories or carbs, you must increase protein or you will likely catabolize your own body protein stores. Such stores will come mainly from muscle. As you lose muscle, your resting metabolic rate will decrease. This explains the frequent failures of other diets that count only calories. If insufficient protein is consumed, you lose muscle, your resting metabolism drops, and the weight comes back faster that you can say Oprah Winfrey.

During a low-carb diet, as much as 57% of excess protein consumed is converted in the liver into glucose, a process called gluconeogenesis. This is important because your brain and central nervous system does function better using glucose as fuel, though in a pinch it can use other fuels, such as lactate and ketones. Anticarb advocates never mention this gluconeogenesis effect.

The anti-carb critics like to point out that initial weight-loss with low-carbs is mainly water. As you limit carb intake, the body breaks down carbs stored as glycogen in the liver and muscles. Each gram of glycogen is stored with 2.7 grams of water, so when glycogen is broken down into glucose, the water stored with the glycogen is released and excreted.

But many studies have also shown that when different diets with the same number of total calories are consumed, differing only in carb content, the lower carb diets most often lead to increased bodyfat losses coupled with less muscle loss. So it isn't only water, as the anti-carb groups like to say.

A little known fact never mentioned by those who consider low-carb dieting dangerous and ineffective,is that there is no nutritional requirement for carbohydrates. How can this be? Simple. As noted earlier, the body is capable of converting other nutrients into the required glucose, such as amino acids, lactate, and even glycerol, which accounts for 10% of the triglyceride (fat) structure. This process is called gluconeogenesis. What is needed, however, are the other nutritional factors often found mainly in higher carb foods. These include fiber and various phytochemicals that are associated with preventive effects against the primary killers: cardiovascular disease and cancer. Later, we'll see how this potentially serious drawback of low carb dieting can be dealt with.

Can you live without ingesting any carbs? Many bodybuilders who've ingested a zero carb diet usually live to tell about it. While it's true that such stringent carb control is most often a temporary eating plan, such as for precontest fat-loss purposes, some people have stayed on nearly zero low-carb diets for years with no apparent deleterious health effects.

One example of such people are the Intuit or Eskimo people. Since such carb staples are fruit and vegetables aren't readily available in the Arctic tundra, the Intuits subsist on diets containing mainly protein and fat. A famous Arctic explorer, Vilhjalmur Stefansson, tried the Intuit diet of meat and fish, finding he felt ill only when he cooked the fish to make it more palatable. Later, he and a colleague traveled North again, and dined with the Intuits and their limited and "dangerous" diet for nearly 5 years, with neither man suffering any ill effects at all.

In an effort to convince the medical community of the lack of problems associated with Intuit cuisine, in 1928 Stefansson had himself admitted to Bellevue Hospital in New York for a year of observation. This observation didn't involve any mental problems, as Bellevue is usually associated with, but rather involved an extended metabolic study to access the long-term effects of low-carb eating. Despite deriving 80% of his daily calories from fat, at the end of the study, Steffansson was not only healthy, but showed a decline in blood cholesterol levels.

In fact, most of the recent studies that have monitored typical popular low-carb diets have likewise shown effects considered to be beneficial for cardiovascular health. This is true despite the stern warnings from anti-carb advocates, who say that the higher fat intake characteristic of lower carb diets leads to inevitable cardiovascular complications.

In the most recent study, presented at the 2002 meeting of the Scientific session of the American Heart Association (AHA), Dr. Eric Westman of Duke University compared a low-carb diet to the Step-1 low-fat diet suggested by the AHA. Those on the low-carb diet consumed a mere 20 grams of carbs daily, with 60% of total calories derived from fat. The results showed that those on the low-carb diet lost 31 pounds compared to 20 pounds on the AHA low-fat plan. The low-carb group also showed a 11% rise in protective HDL cholesterol, with a 49% drop in blood triglycerides (Fat). Those following the low-fat diet showed no change in HDL, and a 22% drop in triglycerides. These results concurred with an earlier study that also lasted 6 months conducted by Dr.Westman.(1)

In another study presented at the same AHA meeting, researchers from the University of Washington in Seattle and the University of Cincinnati showed that after 6 months of following either a low-fat or low-carb diet, only those in the low-carb group showed reductions in C-reactive protein, a blood marker of inflammation that recent studies show is more important in predicting cardiovacular disease than cholesterol levels.

Another study(2) found that a group of men consuming a diet containing only 8% carbs also showed several beneficial cardiovascular changes. These men showed a 34% drop in resting insulin levels, and a change in their LDL cholesterol that is considered beneficial for cardiovascular health. In another study using the same subjects(3), 70% of the weight-loss during the diet was linked to the lower insulin levels. This study also showed no bad effects on any measured hormones during the diet, including growth hormone and testosterone. Thyroid function also wasn't affected. Most impressive, however, was the finding that the entire weight loss during the diet consisted oly of fat, with an increase in muscle mass.

The study authors suggest that the elevated ketones that occurred during the diet may have helped to spare muscle, though the don't rule out other possible explanations, such as greater growth hormone activity during the diet. This is a plausible theory, since excess carbs always blunt GH secretion.

Still another study(4) found that when people with hyperinsulinemia consumed either a high carb or a low carb diet for 4 weeks, those consuming the low carb diet lost greater amounts of body fat. This shows that if you do secrete excess insulin with a meal, as do most people with excess bodyfat, insulin control does indeed make a difference.

Dealing with low carb problems
While low-carb dieting is an effective way to lost excess bodyfat while maintaining muscle, there are several potentially serious problems associated with it. As noted earlier, a combination of restricted carb intake combined with increased protein tends to shift the body toward a higher acidity state. The increased acidity,in turn may cause a loss of calcium from the body and other problems involving kidney function.

One possible remedy for this upgraded acidity is to ingest potassium carbonate. While sodium carbonate, better known as baking soda, is more available, it contains too much sodium. Studies have shown that providing potassium bicarb neutralizes much of the increased acid that results from low-carb dieting, and also helps to preserve lean tissue.

Another, far more simple way to offset increased acidity involves ingesting alkaline foods. But most such foods consist of fruits and vegetables. While you must be judicious with fruit intake during ultra low-carb periods, such as ingesting less than 20 grams of carbs daily, such low carb intakes aren't necessary for efficient fat loss. As such, it's a good idea to consume some low glycemic index fruits and vegetables.

Besides combating the increased acidity resulting from low-carb, higher protein intake, fruits and veggies will also provide several essential nutrients usually lacking in most low carb diets. Low carb diets provide a diuretic action, resulting in a considerable loss of sodium and water. But other minerals are lost as well, such as potassium. When potassium levels drop,such symptoms as muscle cramps and weakness soon ensue. You can take supplemental potassium to offset this effect, but such supplements in tablet form are highly irritating to the gastrointestinal tract. Fruits and veggies are a far better source. Another possibility is using salt substitutes containing potassium chloride.

Fruits and veggies also provide a cornucopia of substances called phytochemicals. These substances,which number in the hundreds, provide potent protective effects against most degenerative diseases,such as cancer and cardiovascular disease. Most are not yet available in supplement form. In fact, I believe the lack of such nutrients is the primary problem associated with typical low-carb diets. Fruits and veggies will also supply the required fiber often missing from low-carb diets. Lack of fiber will cause various problems, ranging from constipation to hemorrhoid flareups. You can,however, get fiber from unprocessed wheat bran and various soluble fiber supplements.

In fact, several supplements are advisable during low-carb diets. These include a multi-vitamin rich in antioxidants; vitamins C, E, and others. A good multi-mineral is vital to offset the lack of calcium and other minerals that can accrue from a deletion of dairy products.

While fat is almost irrelevant during low-carb dieting, I still think it's important to ensure an ingestion of essential fatty acids,such as omega-3 fatty acids. You can get such essential fats from consuming fattier fish, such as salmon and halibut. Eat at least 4-5 servings of such fish each week,the more the better. Omega-3 offers the added bonus of increased insulin sensitivity, thus making a low-carb diet even more effective. Those who hate fish can use fish oil supplements, taking at least 5 grams daily.

Also, as I've previously reported in Ironman, several studies clearly show that active people can consume surprisingly large amounts of carbs right after a workout, with none of it either inhibiting fat loss or converting into fat. Carbs consumed shortly after training are used to help synthesize depleted glycogen stores in muscle, which is the top priority of the body at that time. Adding protein to the mix works even better, and will significantly aid workout recovery and foster an anabolic environment conducive to building muscle.

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1. Westman EC, et al. Effect of 6-month adherence to a very low carbohydrate diet program. - Am J Med 2002;113:30-36.

2. Volek J, et al. A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. - J Nutr 2002;132:1879-1885.

3. Volek J, et al. Body composition and hormonal responses to a carbohydrate-restricted diet. - Metabolism 2002;51:864-870.

4. Torbay N, et al. High protein vs high carbohydrate hypoenergetic diet in treatment of obese normoinsulinemic and hyperinsulinemic subjects. - Nutr Res 2002;22:586-598.

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