An Introduction To Low Carb Dieting: Do Low Carb Diets Work? Are They Dangerous?
Low carb dieting isn’t as popular as it was a few years ago, but it has been going in and out of style since Dr. Atkins first published his extremely popular “Atkins Diet” back in 1972. Even today, the topic pops up at parties, at the gym, on the radio… everywhere!
If you’re new to low carb dieting, you’re probably wondering what it is all about. You’re probably wondering if there’s any truth to “supposed” dangers of low carb dieting as raised by mainstream nutritionists and some medical professionals. I’ve no doubt you’ve heard lots of conflicting data about the safety and dangers of such diets as well as wondrous testimonials.
And last of all, you’re probably wondering if low carb dieting really works. Well, if that’s where you are…
… you’re in the right place!
Let’s get started by taking a closer look at low carb dieting…
The term “low carb dieting” is actually a bit of a misnomer. While most low-carb diets (Atkins diet, Protein Power diet, and to a lesser extent, the South Beach diet, etc.,) start with a period of extreme carbohydrate restriction, this period is generally very brief—a couple of weeks at most.
For obese individuals experiencing extreme insulin resistance, this period of restriction may be extended for a month or two, but in general, extreme, long term carbohydrate restriction isn’t practical for most people.
After the initial period of restriction, most low carb diets allow “friendly” carbohydrates (i.e., low glycemic fruits and vegetables and small amounts of moderate-glycemic carbs), to be slowly re-introduced into the diet.
At this point, the typical low-carb diet can be more aptly described as a “smart carb” diet. In other words, you will have eliminated all the highly refined, processed, and “sugary” foods from your diet, and replaced them with high fiber fruits, vegetables, grains and legumes. You will be eating much more protein than you were previously accustomed, but this is a positive aspect of any diet (and the average North American is deficient in protein).
So why restrict carbohydrates?
The reason for the restriction of carbohydrates is to re-establish the body’s sensitivity to one of the main metabolic hormones, insulin.
In the presence of the North American diet — i.e., one exceedingly high in refined grains, sugar, and processed foods — the body becomes resistant to the effects of insulin.
Insulin plays many vital roles in the body, but for our purposes, its job is to lower blood sugar levels by shuttling it where it is needed in the body. As the body becomes resistant to insulin, more and more of it is required to lower blood sugar levels.
Elevated levels of insulin leads to bodyfat accumulation, excessive cravings for sweets, periods of lethargy and possibly depression (even “crying” spells), and wildly vacillating energy levels. Worst of all, advanced insulin resistance is only a hop and a skip away from Type II diabetes.
If you are overweight and experience intense cravings and a lack of energy, chances are you are insulin resistant.
By virtually removing carbohydrates from the diet, and replacing them with fats and protein (which are satiating and have little effect on blood sugar levels), the induction period of the low carb period re-establishes the body’s ability to deal with carbohydrates effectively. Just as importantly, it switches the body from a carbohydrate-burning machine to a fat burning machine. In other words, in the absence of carbohydrates, the body has to turn to fat as its main source of energy.
OK, but what about the safety concerns of low-carb dieting as raised by mainstream nutritionists far and wide? For instance…
Is it true that the low-carb diet is nutritionally deficient? Well, any nutritionist who tells you so is ignoring several important factors…
- During the short, extreme carbohydrate restriction period of any good low carb diet, it is highly recommend you supplement your diet with vitamin supplements to ensure you are obtaining all your nutritional requirements. Almost all low-carb diets make this recommendation.
- The vast majority of the North American population’s diet is already nutritionally deficient. In other words, even if the low carb diet is nutritionally deficient, which it is not, it would not be creating a new problem.
- Once the short period of extreme caloric restriction is over, the sort of carbohydrates that are re-introduced back into the diet are exactly those that are rich in vitamins, minerals, antioxidants, and fiber. In other words, after the period of extreme low carb restriction, most “low carb” diets become nutritionally dense and diverse.
What about other safety concerns you may have heard raised, like this one…
A high protein diet is dangerous.
There’s isn’t a single medical study indicating this the case. None of the experts making such claims have been able to dredge up a single example of renal failure—or any other danger—as a result of this diet.
I could not find any evidence that an increased protein intake posed any dangers to “normal” individuals not suffering from renal disease. In fact, I found the contrary (see Nutr Metab (Lond). 2005 Sep 20;2:25)…
“…we find no significant evidence for a detrimental effect of high protein intakes on kidney function in healthy persons after centuries of a high protein Western diet.”
One review (Contrib Nephrol. 2007;155:102-12) proposed…
“… that the concept that protein restricted diets decrease the risk of developing kidney disease in the general population is not supported by the scientific literature.
This one, which investigates a higher level of protein intake for athletes (see Appl Physiol Nutr Metab. 2006 Dec;31(6):647-54) indicated…
“…that higher protein diets have quite consistently been shown to result in greater weight loss, greater fat loss, and preservation of lean mass as compared with “lower” protein diets.”
Of course, there are issues when increased protein is NOT a good thing — anyone with less than optimal kidney function needs to be concerned about increasing their protein intake without first consulting with a medical professional.
And as Elissa points out in this blog post, diets rich in cereals/grains, animal proteins, and salt (like the typical North American diet) can get a condition known as chronic metabolic acidosis (CMA). That aside, the available evidence indicates an elevated protein consumption is not dangerous.
Even better, other recent studies indicate protein actually increases post-meal thermogenisis, or fat burning (see Journal of the American College of Nutrition, Vol. 21, No. 1, 55-61 2002).
So if you hear someone say that a high protein diet is dangerous, challenge them. Ask “where’s the the clinical evidence that indicates this is so?” Simply saying that such a thing is common knowledge is neither sufficient evidence, nor is it remotely reflective of what has been proven, scientifically.
What about this concern?…
Increased fat intake leads to higher cholesterol levels, and increases chances of heart attack. Any diet that place an emphasis on the consumption of fatty foods can’t be good for you, goes the argument proposed by mainstream nutritionists.
Unfortunately, there is no evidence this is so. In fact, a recent 20-year study found no association between low carb diets and the risk of coronary heart disease. In other words, this “danger” is not a danger at all.
It’s also been demonstrated that it’s the low carb diet that is more effective at improving metabolic syndrome!
Another common concern with the low carb diet?
Ketones, which are created in the body when fat is burned for fuel, are dangerous.
Again, there isn’t any evidence to indicate this is so. In fact, as evolutionary creatures, our hunter-gather ancestors would have been in a state of ketosis fairly often. Without the ability to grow and harvest crops, and at the mercy of the growing season, total reliance on animal protein for survival was not an uncommon occurrence. Consequently, the body has no problem dealing with ketones.
Bottom line—does low-carb dieting work?
In a word—absolutely. A recent study in the prestigious New England Journal of Medicine showed that dieters on the Atkins diet lost twice as much on those on a the typical low-fat diet recommended by most health professionals (see N Engl J Med. 2003 May 22;348(21):2074-81). Another long term study (see Ann Intern Med. 2004 May 18;140(10):778-85) concluded…
“Participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet.”
On a personal level…
Being hypoglycemic myself, I eat a “smart-carb” diet. That means I rarely eat high glycemic foods (breads, bagels, breakfast cereals, sweets). My carb intake consists of a limited amount of moderate glycemic foods (like pasta, rice, potatoes — usually restricted to weight training days), and an unlimited amount of low glycemic foods (like apples, grapefruits, peaches, greens, tomatoes, peppers, green beans, etc.). This helps keep me lean, and with stable blood sugar levels throughout the day, I rarely experience energy fluctuations.
While this is anecdotal, I personally have seen the greatest transformations in people implementing the low carb diet. In several cases, these diets have been doctor monitored and have lead to decreased bodyweight, a vastly improved blood lipid profile, and a decrease in cholesterol levels.
Best of all, the most user-friendly low-carb diets are dead easy to implement — eat all the eggs, meat, cheese as you want, as long as you don’t eat anything else.
So the $10,000 question is…
Should you go on a low carb diet?