Remembering Kevin Moore

What Is A Low-Carb Diet? Researchers Have Now Defined It!

We already know what the “low-carb” nutritional approach is, right?

What is a low-carb diet? That seems like such an elementary question to ask, especially to people who are already following Atkins, Protein Power, or any of the many other respected and proven carbohydrate-restricted nutritional approaches that have emerged over the years. And yet defining what “low-carb” means is an important distinction since there is debate over how low you should go and at what point carb intake is no longer considered low.

Organizing a virtual who’s who of low-carb diet research and practice, a review article published in the journal Nutrition and Metabolism last year attempted to come to a consensus on what constitutes a low-carb diet. You may recognize a few of the names featured on the expert panel shaping this definition: Dr. Richard Bernstein, Dr. Annika Dahlqvist, Dr. Richard Feinman, Uffe Ravnskov, Dr. Jeff Volek, Dr. Eric Westman, Dr. Jay Wortman and Dr. Mary Vernon, among many others. The collective wisdom of this group of highly-qualified experts came up with the following:

So, we have three distinct and practical terms and definitions to use now:

Low-carb ketogenic diet (LCKD): less than 50g carbs and 10% calories daily
Low-carb diet (LCD): 50-130g carbs daily and between 10-26% of calories
Moderate-carb diet (MCD): 130-225g carbs daily and between 26-45% of calories

This is the first time we’ve seen actual numbers and percentages applied to what defines a low-carb diet. For researchers who are studying the effects of livin’ la vida low-carb, this will definitely guide them on the right path for determining precisely how many carbohydrates to feed their study participants depending on what they are trying to measure. For the average Joe and Jane looking for a way to lose weight, this also provides some measure of guidance about what plan will work for them and their specific individualized metabolic needs.

The review says that the American Diabetes Association defines low-carbohydrate diets as less than 130g per day or 26% of a 2,000-calorie diet.

We consider this a reasonable cutoff for the definition of a low-carbohydrate diet.

For people who can tolerate carbohydrates well, that may indeed be a good cutoff for them. However, I personally couldn’t eat that many carbs, but some people can. It all goes back to my tried and true philosophy that people need to find what works for them and stick to it. As is often stated by members at my forum, “your mileage may vary” (YMMV) and you should adjust accordingly to what suits you best for managing your weight and health.

Anything above 130g carbohydrate up to 225g is considered a Moderate-carb diet (MCD) with the average Standard American Diet (SAD) hovering around 300g+ a day being the very essence of a high-carb diet. For anyone suffering from obesity, insulin resistance, metabolic syndrome, pre-diabetes, or full-blown diabetes, these moderate- and high-carb diets are NOT ideal for bringing your weight and health where it needs to be.

The late, great Dr. Robert C. Atkins called for people beginning his version of the low-carb diet to go on what is called a ketogenic dietary plan. For purposes of defining terms, the panel came up with Low-carb ketogenic diet (LCKD) for people who consume less than 50g carbs daily and carbohydrate comprising 10% or less of total calories. This is where most people who follow the early phases of a plan like The Atkins Lifestyle stay until they reach their goal weight and enter the maintenance phase. However, some people like myself have to stay at a LCKD for the rest of our lives because our bodies are so sensitive to carbohydrate that our weight and health would become worse otherwise.

There is a separate subset of the LCKD for people who consume less than 30g carbohydrate a day known as a Very Low-Carbohydrate Ketogenic Diet (VLCKD) that “should be reserved for the therapeutic approach to epilepsy” according to the panel. As we have heard from proponents of ketogenic diets for epilepsy like Dr. Deborah Snyder, this way of eating provides an effective means for treating seizures in children stricken with epilepsy. The panelists making this designation say “these diets do not independently specify the level of carbohydrate, but rather the sum of carbohydrate and protein.” That’s not to say a non-epileptic cannot or should not consume a “ketogenic” diet, but it should not be described that way clinically for people using it for weight loss purposes.

One interesting aside about low-carb dieters that is mentioned in this review paper defining what a low-carb diet is concerns dietary fat. Oftentimes we hear about how an Atkins-styled low-carb diet is also very high in fat as a percentage of total calories and this is true by definition that a low-carb diet must be higher in fat. But does this mean people who are livin’ la vida low-carb are stuffing their mouths with gobs and gobs of added fat from butter, meat, cheese, and more compared to what their diet used to be? The researchers don’t think so.

In practice, many low carbohydrate dieters do not add additional fat.

They note this was observed in studies conducted by Boden, LaRosa, Yancy, and Volek and that it was the percentage of fat calories that increased rather than the actual amount of fat consumed. However, they do acknowledge there are some people who do increase their fat consumption habits.

Not everybody on a low carbohydrate diet follows this pattern, but a recommendation based on this behavior would seem more appropriate than unqualified rejection of low-carbohydrate diets.

Turning to the subject of diabetes, the panel states that although low-carb professionals like Dr. Richard Bernstein call for a very low-carb intake to best manage the disease, they believe “all options may be considered and therapeutic choices can be determined by individual physicians and their patients.” Realizing that many people equate the phrase “low-carb diet” with the “highly controversial” Atkins diet, they share that carbohydrate control “has many implementations and the severity of the epidemic of diabetes makes it appropriate to go beyond historical controversy and analyze dietary interventions as they are actually implemented.”

On the issue of compliance, the researchers proclaim that the effectiveness of low-carb eating and the ability of dieters to remain on such plans are “separate phenomena.”

In fact, all recommendations are specifically intended to be different from average consumption and it is sensibly the purpose of health agencies to encourage conformance to the best therapies.

And this should include livin’ la vida low-carb! With the emergence of solid scientific date supporting low-carb diets, they conclude that “it is time to re-appraise the role of carbohydrate restriction.”

Although pessimism exists in the medical community on the efficacy of any diet in the treatment of Type 2 diabetes and metabolic syndrome, the success of carbohydrate restriction for many practitioners and individual patients mandates that we should determine how this approach can be consistently and effectively employed.

And it is the success seen by real people being treated for obesity and disease like diabetes that led these low-carb researchers and medical professionals to come up with these definitions to aid other doctors and people observing low-carb diets to give them a serious second look. Simply disregarding low-carb based on a preconceived idea about what it is does nothing to further the discussion of optimal diets for combatting the weight and health woes of society. This isn’t a low-fat versus low-carb thing as is often portrayed in the media and perpetrated by the extremists pushing one or the other diets out there. It’s about what works and can work for many more people if it is given a fair chance to be presented as a healthy and viable option.

Interestingly, while low-carb diets have been so vilified by the so-called health “experts” and the like over the years, the researchers acknowledge that anecdotal evidence suggests “carbohydrate restriction is a common clinical recommendation for diabetes” and that there is “a need to codify these recommendations in light of current evidence.” Amen to that! Too many diabetics are walking around right now wondering what’s wrong with their blood sugar and A1c levels because they’re eating the ADA-recommended diet but still need to use insulin to manage their diabetes. Carb control should at least be promoted to people first over medications and insulin!

Finally, the researchers conclude that the time is right based on what we’ve seen in clinical practice, learned from basic biochemistry, and what causes metabolic syndrome that a serious “evaluation of the efficacy and safety of carbohydrate-restricted diets for the treatment of type 2 diabetes” is sorely needed.

The fact that carbohydrate restriction improves markers of cardiovascular health, even in the absence of weight loss, sensibly removes historical objections to the dangers of this approach. A critical re-appraisal could form the basis for an alternative for those patients for whom current recommendations are not successful.

And I’ve been saying this for years now — if the Atkins low-carb diet works for certain people where a low-fat diet has not, then why not recommend it alongside as a reasonable alternative approach? That’s why these researchers took the time to define what low-carb is and now that they have there is no excuse for the terminology to be misinterpreted by anyone in the medical, research, or health establishment again. The bottom line for you and me is to find out at what level carbohydrate-restriction is necessary for managing your weight and health. Some may be able to eat a MCD while others like me need to stay on a LCKD. Discover what works for you, follow it exactly and then stick to it for life! Regardless of what pathway you choose, be confident you are making choices that will positively impact your life for many years to come.

Special thanks to Dr. Richard Feinman for putting this panel of low-carb experts together to come to a clear-cut definition of what low-carb means. You can e-mail your appreciation to him at info@nmsociety.org. And if you support this kind of research and analysis into carbohydrate-restricted diets, then consider joining Dr. Feinman’s Metabolism Society to add your name to those being counted as standing for “truth in science…to increase awareness regarding proper nutrition and health.” What a perfect gift for yourself or anyone you know who loves livin’ la vida low-carb and wants to see the truth about it pierce through our culture.

  • Nancy

    in general this all sounds great! 130 carbs though, that is way way too much for me, I have to stay UNDER 50 carbs a day just to maintain my weight and if I start sneaking carbs in, I FEEL horrible, get headaches, have stomach trouble, the whole nine yards.

    Me too, Nancy! I think these guidelines help people who are clueless, though.


  • Wow, wonderful information, Jimmy. I think metabolism history has a great deal to do with how many carbs a person can tolerate. With the rate of insulin resistance present in society today, it’s no wonder why so many people have trouble even on moderate carb diets.

    It’s also important to note that some people can’t lose weight with certain types of carbs. And I don’t mean junk carbs, I think we all know that! But many people are sensitive to grains (even gluten free), and find it much easier to restore health when all grains are limited.

    I generally keep my carbs somewhere in between 50-100 grams per day, mostly from raw dairy and fruit. I find this amount keeps me happy and at a healthy weight.

    Elizabeth, you are probably closer to being the norm than the exception I’m sure. :)


  • Nice article Jimmy. Good to see some standards being set. Hopefully they’re followed! I hate seeing those studies where they have goofy macros on the mouse chow. The last big high fat make you stupid study where is was high fat (veg oil) and 40% carbohydrate or somethign ridiculous.

    I noticed right off, the guidelines are nearly the same as Mark Sisson’s Primal Blueprint carbohydrate curve. I was a low-fat guy before going primal, so I never paid much attention to carbs until then.

    I love food pyramids :) I even built myself one for my Paleo diet post.

    Excellent stuff, Grok! I think the key is remembering we are all different and have various tolerances for carbs.


  • Sue

    Moderate carb up to 225g seems quite high but some people can handle it.

    THANKS Sue, I agree. Unfortunately, I’m not one of them. :)


  • Ken

    Great post, Jimmy! If this prompts some dialog and breaks the log jam of resistance to low carb it is all good. As an over weight type 2 diabetic I am doing well on the LCKD and look forward to a time when I might be able to move to LCD. Thanks.

    Keep at it, Ken!


  • Ailu

    This low-carb food pyramid is soo wrong. First of all, eggs should be down at the bottom with protein, and then the remaining cheeses should be shared on the same row as the nuts above. Then the veggies should be brought down to where the cheeses were. That would be a much more accurate picture of a healthy low-carb diet, imo.

    all your veggies
    all your proteins

    THANKS for sharing your opinions about the kind of low-carb diet you follow, Ailu! Not everyone would agree that you need to limit fats as much as you are saying, but I can appreciate where you are coming from. :)


  • When considering a low carb diet it is just as important to consider the quality of the carbohydrates as the quantity.

    Fruits and vegetables should not be treated equally to processed sugars!

    Thank you for your comments, Dr. Hill! I’ll agree with you that the quality of the carbs is indeed important, but the bottom line is sugar is sugar is sugar. So just because a banana is a fruit doesn’t mean I need to look the other way at the 29g carbohydrate that are in it.


  • Ailu

    @Jimmy: Whoa, wait a minute, You misunderstand, I am totally pro-fat. (yum!) As you can see, I kept fats in the same place as they were. If you are referring to cheeses, they are a much more high density food than veggies, so you don’t have to eat as much of them, to get your fat content, at least compared to veggies. I was stacking them according to volume, not density. If I look at it density-wise, well, then this chart makes much more sense. Is that the correct understanding?

    I would look at it for caloric density. :)


  • Hi Jimmy,
    I’ve been enjoying your posts, and enjoy sharing/spreading the message, too. As a Cert. Personal Trainer, and Nutritional Coach, giving people basic guidelines and info like this, is a great way to get started. Like you, I agree that everybody is unique. What we put into our body must make sense to the individual. After many years of trying nearly EVERY diet out there, I currently practice IF, and hover around 50g carbs per day (mostly green/fibrous).
    One thing that I find with many of my clients (and thru my own experimentation) that works well is macronutrient balance…the lower the carbs, the higher the fat…and generally keeping protein in the middle.
    Too make it work, little lifestyle changes will allow for a ‘fruit’ful life, not just an existance :)
    Be Well,

    THANKS for doing your part in this health crusade, Max! :)