High-protein, low-carb diets: Are they healthy?
The straight goods on a healthy program that lets you slim down and have your carbs, too
by Anne Lindsay


By now most of you have likely heard or read about the high-protein, low-carbohydrate diets that have been the rage among the overweight. You may even be like some of my friends who are following Mastering The Zone, or Dr. Atkins' New Diet Revolution, or Protein Power. They tell me how much weight they've lost and how good they feel. What's more, some dieters find the high-protein, low-carbohydrate diets easy to follow because they don't have the hunger and cravings associated with most diets.

I tell them that of course they'll lose weight on these diets – after all, they're reducing their calorie intakes. But high-protein, low-carbohydrate diets prompt the body to make an excessive amount of chemicals called ketones, which creates a state known as ketosis. This state makes dieters feel queasy and light-headed and lose much of their desire for food. Lose the desire for food? Great, you say. Why not simply stay on these diets and be eternally thin?

One reason is that the authors of most of these diet books have never published data to validate their claims. Low-carbohydrate diets do work in the short run. For certain medical situations your doctor may even recommend one.

However, there are several downsides to following a high-protein, low-carbohydrate diet for a prolonged length of time. Now a little-known but well-researched book, The Glucose Revolution, explains why you should eat carbohydrates and how you can lose weight while including them in a balanced, healthy diet. It recommends certain carbohydrates according to their ranking on the glycemic index (GI), a rating system that shows how quickly various carbohydrates raise blood-glucose levels.

Diet theories
Most of the best-selling diet books are based on the premise that a diet high in carbohydrates causes a rise in blood-sugar levels, which results in high blood-insulin levels. They conclude that high blood-insulin levels result in weight gain.

The Glucose Revolution, which refutes much of the popular (and unproved) diet information on carbohydrates, was written by Canadian Dr. Thomas Wolever, a world-renowned expert on glucose. Wolever, who is also a professor in the department of nutritional sciences at the University of Toronto, wrote the book along with three other nutritional and medical researchers.

All the books agree that high blood-insulin levels are associated with obesity. But Wolever and his coauthors disagree with the other authors on how to lower those levels and what constitutes a healthy diet. Their book shows why we should eat a carbohydrate-based diet, how we can do it and lose weight, and how to control our blood glucose (Dr. Wolever says that the term blood sugar is technically incorrect). It also shows that we gain weight only when we eat more carbohydrates than we need for energy.

Fast foods
Wolever helped develop the glycemic index with Dr. David Jenkins at the University of Toronto. The index ranks carbohydrate foods by their immediate effect on the body's blood glucose. Foods with a low GI raise blood glucose the least. If we eat carbohydrates that have a low GI we can control our blood-glucose levels and our insulin levels. (Remember, high insulin levels are associated with weight gain.) This means we don't need to follow a restrictive and unbalanced low-carbohydrate diet to lower insulin levels and lose weight.

Quick digestion results in a fast rise in blood-glucose levels, which in turn causes a rise in blood-insulin levels. We used to think that our bodies digested simple carbohydrates (in the form of simple sugars, such as candy or sweets) quickly. We also thought that we digested complex carbohydrates, such as breads, pasta and rice, slowly. Wolever points out that our assumptions about the speed at which foods are digested were wrong. Many starchy foods, such as bread and potatoes, are digested quickly, while moderate amounts of most sugary foods, such as candy and ice cream, won't produce huge surges in blood glucose.

Research reported in The Glucose Revolution shows that slower digestion helps to delay hunger pangs and promote weight loss in overweight people. Low-GI foods help you to burn more body fat and less muscle.

Wolever says that other popular diet books use the glycemic index but they misrepresent it. “Any book that cautions against pasta isn't right,” he notes, since pasta has a low GI. As well, some very nutritious foods, such as fruit, have a moderately high GI ranking but shouldn't be avoided. “It's important to eat a variety of foods,” he says. “Just include more carbohydrate foods with a low GI.” And avoid highly refined foods.

The bottom line: To lose weight you still have to exercise and limit calories. You can lose weight on high-protein, low-carbohydrate diets, but following them is not smart eating. Eat a healthy, balanced diet – one that doesn't severely restrict foods you love to eat.


Canadian Living, March 2000

In this article and others I have read, and in talking with my own doctor, I find that there seems to be a common misconception that a low-carb WOE is actually a no-carb diet.

My doctor had pretty much the same thing to say about low-carbing -- it's not sustainable.

I disagree. A no- or very very low-carb diet may not be sustainable, but a WOE rich in proteins and fats and limited in carbs to what you really need is sustainable. There are plenty of people who do that when they achieve their goals and go to maintenance eating.

Also, the author mentions people's feeling queasy and light-headed. I never have. I haven't felt better in my whole life, including when I was a kid.

;-Deb

It's worth noting the date of this article, March 2000. Because the Drs Eades published Protein Power Lifeplan in October 2000 --- the bibliography of research papers and scientific and medical references was so HUGE, it would've added too many pages to the final manuscript. So, it's published online at http://eatprotein.com/bib_pplp.php3 .....

In addition, so is the full research bibliography for their first Protein Power book .. http://eatprotein.com/bib_paper.php3

The bib. list is also available in print, if you send a SASE to their office; the address is in the book or on their website.

Atkins has posted an extensive list of research papers supporting low-carb and health; most of these were published before 2000. Check them out http://atkinscenter.com/dev/science/index.html

I do enjoy Canadian Living magazine, but it's worth noting that they are dependent on the commercial support of many processed food manufacturers, cereal and pasta companies, etc, etc, etc.



Doreen

Not to mention, says she cynically, that Anne Lindsay has written a number of low fat cooks (two of which I own--but they're in the basement).

Susan

Isn't it true there has to be some balance between calories used and eaten?

Hi Pete,

This is the general low-calorie theory.

For low-carbing, the emphasis is not on calories, it is on metabolism and insulin control.

It would be well worth it if you invest in a low-carb book to learn more about it. Best bets is the Protein Power and/or the new Atkins book.

Wa'il

Isn't it also interesting that it is a common misconception that low carb (which means no carb-ha) also automatically means high protein (and therefore bad to your kidneys). I eat more veggies with this WOE than when I eat low fat/high carb! Plus I feel LOTS better!

-animaldoc

AnimalDoc said, "misconception ... also automatically means high protein."

So true! I eat more vegetables (mostly non-starchy) than I ever ate before. I think I used pasta, bread, and rice to keep from having to eat my veges. I am finally learning to like them in order to live my new WOE. Also, I am NOT eating that much more meat.

;-Deb

Wa'il,

Is there a chapter or two that you can refer me to in either book that gives an overview of metabolism and its role in weight loss in context of a low-carb diet? I'm interested in understanding how this works.

Sure thing Pete,

Check chapter 5 in the latest Atkins (2002) "Understanding the importance of Insulin" or chapter 3 of Protein Power "Excess Insulin and the Insulin Resistance Syndrome".

Chapter 6 of Atkins "Lipolysis" as well. I like the new edition of Atkins, simply due to one thing, each and every claim has a note referring to studeis proving that specific point, with the page numbers in the studies.

Not to say the rest of the chapters aren't important, but those are the "guts" of the scientific basis.

My own simplistic analogy for why the calorie theory isn't valid, is that it only considers thermodynamic factors of food (energy) and totally ignores biochemical factors in food metabolism.

Wa'il

Wa'il

Okay thanks, I'll go with Atkins. It should make some interesting reading on March break. Intuitively, I always thought there might be some differences in certain foods because of chemical and other factors - let's see if Atkins can shed some light on it for me.

Wa'il have you read any Barry Grove? He does a pretty good job explaining why a calorie isnt just a calorie - I think nsmith did a pretty good review of his book in the Plan Comparison forum.

Nat

I think Dr. Schwarzbein's book explains it pretty well also.

And when you think about it, look at a label: If fibre is listed as part of the carbs, you should subtract the "calories" assigned to that portion because fibre is not metabolized.

Just a thought...
;-Deb

I didn't see this article in Canadian Living, but it was featured on MSN.ca home page yesterday.

I was pretty disappointed, but I also had to laugh. The reason low-carbers lose weight is because they reduce their calorie intake? She really hasn't been paying attention.