What Exactly is a "Low-Carb" Diet Anyway?

Having just finished the revised and expanded edition of my 2004 best-seller Living Low Carb (out in January, in case you were interested!), I've been thinking a lot recently about low-carb diets.

Specifically, I've been thinking about definitions.

How exactly do we define low-carb, anyway?

For years, low-carb suffered from bad publicity. Atkins- a superb nutritionist and very smart guy- couldn't shake the stigma of recommending "pork rinds" (a recommendation that was taken out of context) and people who didn't know any better thought his diet forbade all carbohydrates (it most certainly doesn't).

Then there was the ketosis confusion. Ketosis- a harmless metabolic state that the body goes into when carbohydrate intake is very low- became identified with low-carb diets largely because early editions of Atkins' books stressed ketosis as a desirable goal for the first stage of the Atkins diet (which limited carbs to 20 grams a day).

But very few low-carb diets put the body into ketosis.

Then there was the American Dietetic Association and its spokespeople, who frequently have a questionable relationship with the truth. These folks even characterized Barry Sears' "The Zone" as a low-carb diet (even though the majority of calories on the Zone Diet come from carbs!)

So what exactly is a low-carb diet?

The American Dietetic Association designates "low carbohydrate diets" as less than 130 grams a day (or 26% of calories from a 2000 calorie diet). Though I hardly think this is "low", it seems to be a decent working definition, given that most Americans consume a whopping 300 grams of carbs a day! (Just for the record, carbohydrate consumption before the epidemic of obesity averaged 43%, just about what is recommended by Dr. Sears in "The Zone".)

According to Richard Feinman, PhD, Professor of Biochemistry at SUNY Downstate Medical Center and head of the Nutrition and Metabolism Society (of which I am a proud member), 26%-45% of calories from carbs is a good range for what we might call "moderate" or "controlled" carbohydrate eating. According to Feinman, less than 30 grams a day should be referred to as a "very low carbohydrate ketogenic diet"; the term "ketogenic diet" should be reserved for the therapeutic approach to epilepsy, for which it works quite well.

Some low-carb diets for weight loss limit carbs strictly (20-30 grams) for the first couple of weeks (the Atkins Induction Phase), then add them back gradually. Many health professionals and weight loss experts believe that you can get most of the benefits of "controlled carb eating" with anywhere up to 100 grams a day. In a recent blog, I talked about a study in which they used a vegan version of Atkins that contained 130 grams of carbs a day and everyone still lost weight and had improvements in their risk factors for heart disease to boot.

Remember- hard as it is to believe- your body has no physiological requirement for carbohydrate. That's not to say you shouldn't eat carbs- you should!

But if you're looking to lose weight and improve your health, you should get the vast majority of them from vegetables and fruits.

Carbs from fruits and vegetables are loaded with vitamins, minerals, phytochemicals, fiber and other good stuff that your body thrives on. And you can eat more vegetables and berries than you can imagine and still stay in the range of 100-130 grams of carbs a day! Add to that about 100-120 grams of protein and about 60 grams of fat, and you've got a blueprint for health and weight management that will work for just about anyone.

Modest Carb Reduction May Facilitate Weight Loss

A new study from the Department of Nutrition Sciences at the University of Alabama at Birmingham shows that even a modest reduction in carb intake was enough to stabilize blood sugar, reduce insulin and, in the long-run, facilitate weight loss.

Barbara Gower, PhD, the coauthor of the study, said "There has been great public interest in low-carbohydrate diets for weight loss, but they are difficult to maintain, in part because of the drastic reduction in carbohydrates".

Well, we can quibble about the difficult to maintain part- many low-carbers feel it's the easiest program they've ever been on once they get used to it- but let's admit that many people do find the idea of giving up high-carb foods daunting to say the least.

This study shows that even a partial reduction in high sugar (high-glycemic) carbs can make a huge difference to your health and your weight.

The researchers studied two groups of people. One group was given a "standard" diet of about 55% carbohydrates, 18% protein and 27% fat. The second group was given a diet of 43% carbs, 18% protein, and 39% fat.

Calories were identical in both groups, and the calorie level was set at just the amount needed to maintain weight.

The results showed that even when weight loss was not the goal, the group eating slightly lower carbs stayed fuller longer and were more satisfied. They also had healthier blood sugar levels and lower levels of insulin, the fat-storage hormone.

Commenting on the study, which was presented at the 91^st Annual Meeting of the Endocrine Society in Washington DC, Dr. Gower said this: "Over the long run, a sustained modest reduction in carbohydrate intake may help to reduce [calorie consumption] and facilitate weight loss".

Amen to that.

If you'd like a structured low-carb diet plan designed to stabilize blood sugar levels and lower levels of insulin (the fat-storage hormone) check out Diet Boot Camp. It includes a healthy shopping list, quick and tasty recipes, and a food almanac.

Post-Workout Snack? Not so fast...

For years, we've been getting advice on eating and working out that's been lifted directly from the bodybuilding-heavy gym culture of the 60's and from the training manuals of serious competitive athletes. That's why we're told to eat 6 meals a day, have a high-carb snack directly after working out ("to refuel the muscles") and to carb load every time we go for a run.

Turns out that advice is great if you're training for a marathon or for the Mr. Olympia, but it's precisely the wrong way to go for the average exerciser, especially those looking to lose weight.

If you're trying to lose weight, nix the nosh.

In one recent study, volunteers were given high-carb mini-meal immediately after exercising on a treadmill for an hour. Insulin efficiency- the ability to clear sugar from the bloodstream- was completely wiped out by those who had the high-carb drink.

A separate study tested high-carb mini-meals against low-carb ones and found that if you're going to eat after working out, a low-carb meal does the least damage.

"If people are going to exercise to benefit their health, they should not be eating back the calories immediately- or within a couple of hours- of finishing", said Barry Braun, PhD, director of the Energy Metabolism Lab at the University of Massachusetts Amherst. "It seems as though giving people back carbohydrates blunts or diminishes the exercise benefit".

Remember, you'll still get the health benefits of exercising whether you eat afterwards or not.

But if you're trying to lose or maintain weight, it's another story.

Low-Carb Diets Cause Memory Loss? Not so fast!

Recently the media had a field day reporting a Tufts University study that supposedly showed that low-carb diets have a negative effect on memory. Once again, the media got it wrong, and in two critical ways. First, they reported conclusions that were not found by the study and two, they omitted findings that were critically important to understanding what was found.

In the study, half the people were put on a low-calorie high-carbohydrate diet and the other half were put on a low-carb diet. The researchers then gave the participants tests for long and short-term memory and attention after one, two and three weeks on their respective programs.

The first thing to note is that the low-carb group was on a basically no-carb diet, at least for the first week. And they did indeed score slightly worse on the reaction time part of the test that week. (What the media buried deeply in their reporting was that the low-carbers performed better than the other group in tests that measured attention and the ability to stay on task!)

Also buried deep in the reporting- when it was reported at all- was that the low-carbers quickly improved on the tests by the second week.

These results are really exactly as expected. There is a short period of adaptation when the brain and body switches over to ketones as a fuel source, which most certainly was happening in this situation as the dieters were consuming no carbohydrates whatsoever. This adaptation period is natural and mental and physical performance returns as soon as the adaptation period is over. Stephen Phinney, PhD has even done research showing that, after a brief period of adaptation, world-class cyclists on a ketogenic diet are back to cycling at their previous levels of intensity and endurance within a month!

The second detail that was omitted was that limited carbohydrates were introduced in the second week and the performance on the memory tests went right back up.

While the researchers put out a news release saying "diets low in carbohydrates can be detrimental to learning, memory and thinking", this was not what the research showed at all. Larry McCleary, MD, one of the country's top neurosurgeons and author of "The Brain Trust Program" says "There is a groundswell of medical evidence that documents how too much sugar can make the brain shrink, wither, atrophy and just plain work badly".

Last year I told you about a study in the September issue of the American Journal of Clinical Nutrition that compared low-fat to low-carb dieters and found improvements in mood and memory in both groups of dieters. And it's also worth noting that a Colorado biotech company called Accera is currently working on a drug to help the liver create more ketones because their Phase ll studies showed rapid and significant cognitive improvements in Alzheimers when patients were provided with this alternative fuel source.

Let's remember that no one is seriously recommending a no-carb diet. We recommend a controlled carb diet where you reduce the amount of your diet that comes from processed carbs and sugar- as much as possible.

And dangerous as far as memory goes? "If you want to age your brain, just eat the typical diet most Americans consume", says Dr. McCleary.