How Low is Low Carb?

Many agree: People with diabetes should eat a low-carb diet. Last week we looked at what “carbs” are. But what is meant by “low?” How much carbohydrate should you eat?

The Dietary Guidelines for Americans, 2010, (PDF) recommend that healthy people get 50–65% of their calories from carbohydrates. A study posted on the American Diabetes Association (ADA) Web site agrees. For a woman eating a below-average 2,000 calories a day, 50–65% would be 250–325 grams of carb a day.


The Dietary Guidelines call for “a balanced diet that includes six one-ounce (28.3 g) servings of grain foods each day.” This would mean 170 grams of carbohydrate from grains alone each day. And the average American diet includes many other carb sources.

Most men eat closer to 3,000 calories a day, so their numbers would be higher. Sixty percent of 3,000 would be 1,800 calories, equivalent to 450 grams of carbohydrate each day.

Anything less than the recommended range is sometimes considered “low-carb.” Most popular low-carb diets, like Atkins, South Beach, Zone, and Protein Power, are much lower, from 45% of calories down to 5%.

Many diabetes experts recommend somewhat lower carb intakes than ADA does. On our site, dietitian Jacquie Craig wrote, “Most people need between 30–75 grams of carbohydrate per meal and 15–30 grams for snacks.” So that sounds like between 120 and 300 grams a day.

Dr. Richard Bernstein, an MD with Type 1 diabetes and a long-time advocate of the low-carb approach to diabetes, suggests much lower intakes. He says eat 6 grams of carbs at breakfast, and snacks, 12 grams each at lunch and dinner. So that would be about 40 grams of carbs per day.

If 12 grams per meal sounds like a small amount, it is. It’s about the amount in an average slice of bread. And it provides only 48 calories — carbohydrates contain 4 calories per gram — which will not fuel a lot of work.

Even so, according to an article by diabetes educator Gary Scheiner, processing those 12 grams of carbs at lunch might require anywhere from half a unit of insulin to two units or more. If your body does not produce insulin, and none is injected, that one slice of bread can raise your blood glucose significantly, maybe from 5 to 50 points depending on the type of bread and your individual body.

According to Dr. Bernstein, injecting insulin doesn’t solve the problem very well, because it’s extremely difficult to match the peak of insulin action with the peak glucose level from the carbs you ate. That’s why he recommends very small amounts of carbs and very low doses of insulin.

How fast the carbs get into your system as glucose (indicated by the food’s glycemic index, or GI) may also play a role. If a food is slow enough (that is to say, has a low enough GI) and your body releases insulin slowly, it might be able to keep the numbers from going too high. People with diabetes don’t make enough insulin to cover a large dose of carbs, but might manage smaller servings OK.

Many low-carb diabetes advocates agree with Bernstein. Jenny Ruhl, keeper of the Web site Blood Sugar 101, recommends starting at 15 grams of carbs per meal. Other diets, like Atkins’, are even stricter. He recommended starting at 20 grams per day.

Ruhl says, “Adopting these very low carbohydrate limits will control your blood sugar very nicely. But over time, many people find that sticking to a diet this low in carbohydrate becomes impossible.”

So Ruhl and others recommend doing a lot of glucose monitoring at home. Try different foods, in different quantities, and see where your glucose is one hour and two hours after meals. You want to keep it below 140 milligrams per deciliter (mg/dl), because that’s where blood vessel and nerve damage seem to start. Write the results down.

But that’s not the end. Ruhl writes,

If a meal allows you to reach your blood sugar targets, try eating it again on a different day and test it again, possibly at a later time, to make sure that your good numbers weren’t just a result of slow digestion.

If your numbers go a little too high, she suggests trying smaller portions, and eliminating the questionable food if necessary. Because everybody is different, monitoring may be the only way to find out how much carbohydrate you can handle. And different types of carbs may affect you differently.

So, if carbs are the major energy source for most people, and you’re not supposed to eat them, what are you supposed to eat? Is it all meat and eggs from now on? What are the alternatives? The week after next, I’ll get more into what different carbs do differently, and how to know what’s best to eat. I might take next week for an amazing herbal treatment a reader notified us about.

In the meantime, here is a page that gives the precise carb content of almost any food you can think of.

  • Kathleen

    I loved looking at the carb content of all the foods. It is amazing what has carbs and what doesn’t. I am looking forward to what different carbs do.

  • calgarydiabetic

    You wonder if the dietary Gudelines for Americans is causing the diabetic epidemic.

    This may have been an acceptable diet when we went out and plowed 35 acres by horse and plow or cut a cord of wood by hand in a day.

    But sitting 8 hours in front of a computer the demand on the pancreas by an insulin resistant body will lead to disaster for many people IMHO.

  • calgarydiabetic


    Ruhl says, “Adopting these very low carbohydrate limits will control your blood sugar very nicely. But over time, many people find that sticking to a diet this low in carbohydrate becomes impossible.”

    This is just not true. You can train dogs and you can train people. I do not have any carb gravings anymore. In the beginning when I looked at a slice of bread I visually associated it with my brothers gangrened feet the result of eating too many carbs in his old folks home. That was a turn off.

    even now with massive amount of insulin I could eat a bit more carbs but at the expense of weighting 599 lb. No you can find a fine diet from fat, protein and non starchy veggies. And metamucil and ground flax seed to replace the fiber from grains.

  • jim snell

    10-4 Calgary Diabetic. One can stay ona low glycemic diet and maintain the health. The motivation you mention is dead on target. I almost wipped out until I got my diet down to 1200 calories low carb diet. People said I would starve – au contraire.

    Measurement necessary after 2 hours after meal to police peaks and efforts as well as good sufficient exercise is also needed.

    If one does not control the energy input/burn; you will be dying a nasty death and leaving in the Pine Box early. Genetics, environmental and other factors while of interest are no excuse for not properly monitoring ones health and blood glucose status in this present 24/7 oversupply of rich refined foods and dramatically reduced energy utilization/burn. As eloquently stated by Calgary Diabetic; we are not out ploughing the fields with the horse ( walking behind the horse) any more. At best we now would be sitting on the iron horse tractor burning little energy getting fat and possibly type 2 diabetic.

  • Joe

    Back in the “good old days” farmers and lumberjacks still developed diabetes, heart disease and all the rest. Let’s not ignore that things like cholesterol, high blood pressure, and diabetes are largely genetic. That means rather than blame diet for disease, people with predisposition to disease should choose a diet that fits their particular genetics. For me that means balance. My glucose is high on a high carb diet, but it skyrockets on low carb diets. If I eat a well-balanced diet and avoid certain foods that affect me negatively (bread and pasta are not among them, by the way, but most fruit is) I do better. It comes down to knowing which foods generate which reactions and planning accordingly. Exercise too plays an important role, but it doesn’t have to be all day hard labor to make a huge difference and there isn’t much evidence that excessive excercise produces much more results than milder exertion a few times a week. The bottom line is we’re all unique and there is no “one size fits all” solution.

  • Lynne Nelson

    I follow a low carb plan and do not experience carb cravings. I’ve been eating low carb for years and if I increase carbs in my diet I gain weight. I have been able to control my diabetes since the diagnosis 12 years ago by following Atkins and/or South Beach. When I tried to follow the ADA eating plan my glucose readings were very high and I was frustrated. In 2003, I went on the Atkins diet and reduced my weight and changed my eating plan and my blood glucose has been in the acceptable range ever since.

  • joan

    Thank you for the article on Low carbs! I always read Diabetes Self Management news. Of course, whatever method we choose for better control, it really depends on ones individual system.

    I worked out a low carb plan for myself based on what my system would tolerate. It was a Trial and error period and changes still occur!! My daily average of carbs is now around 90 – 100. Totally retired but gardening keeps me active and fit!

    To keep a Daily Log has guided me, supported my memory and still keeps me within a safety net that is comfortable. It also helps my doctors to review and offer helpful suggestions. I am a Type 1 for 56 years.

    My motto: if it hurts do not do that anymore!

  • Andre Chimene

    Dr. Bernstein’s total carb per day recommendations equals 30, not 40. That is for a Type 1 . A type 2 should stay around 50 grams per day…no more. Less is fine if they want better control. Then, moderate the protein. Excess protein turns to glucose thru gluconeogenisis. We diabetics are very good at turning excess protein into glucose. Eat beneficial fat as your main macro nutrient. It is the only one that won’t raise glucose, insulin or leptin.

  • Pam Schmidt

    I have found over the past 7 years of being a type 2 diabetic, that my alloted 45g of carbs per meal is too much for me effectively manage my blood sugar. Breakfast is my hardest meal to cut down on carbs. I can’t face eggs earyl in the morning so I usually opt for a low carb cereal like Cheerios with 23 carbs per 3/4c. serving, then have a scrambled egg a couple of hours later to get a little protein. I take a few supplements hoping that I’m making up for some of the nutrients I miss from the carbs I’m not eating. Fruits don’t seem to raise my BS nearly as much as other carbs, so I do eat more fruit than starches.

  • Sheila M

    I printed out the USDA National Nutrient Database for Standard Reference, but don’t understand what or how to use the information. Can someone simplfy it for me. Thanks

  • Glen A

    The idea of eating 30-75g of carbohydrate at a meal is ludicrous for diabetics, regardless of Type I or Type II, and will result in the vast majority of diabetics being on pharmaceuticals for the rest of their (likely shortened) lifespan due to very poor overall glycemic control.

    I eat 40-60g a day in total, with as many as 3,500 calories (sometimes more) in that day. I’m a severe Type II diabetic with very impaired pancreatic beta-cell function. I produce very little insulin, yet I maintain HbA1c’s in the 5.1 to 5.4% range and have for nearly two years now since adopting a high-fat/moderate-protein/low-carb ketogenic diet. BTW I do NOT inject any basal/bolus insulin whatsoever, even though at diagnosis I had an HbA1c of 12.2% and was told I’d be on it for life…

    Also of note, when you adopt a high-fat/moderate-protein/low-carb ketogenic diet, your body becomes keto-adapted and relies on oxidation of fatty-acids for fuel, NOT carbohydrate. As such carbs are no longer the major energy source for these people.

  • dina

    I’m very confused, I’m on an insulin pump and I need to count every carb,a serving of steamed broccoli or spinach is 15 grams of carbs. So is a small apple. ….so I’m supposed to starve myself? According to this guy, I’m eating way too much because that salad with broccoli, carrots, tomato, fresh spinach and grilled chicken is at least 15 grams of carbs per 1/2 cup, and that’s without any dressing.

    • Notagainboot

      Exercise afterwards. It works!!!! Depending on how much insulin your body still makes is how long you will need to exercise. It will burn off what you just ate…with no problems. Imagine if I told you diet and exercise will solve your problem….or you can just stick to your pump. One day there might be a situation where you won’t have what you need….what will you do then. If you eat with out insulin and practice that for a few weeks you will know how to control it yourself, otherwise your at the MERCY of a drug and not in control.

  • Kathie Swafford

    How many grams equal ?an ounce?

  • bd

    Ruhl says, “Adopting these very low carbohydrate limits will control your blood sugar very nicely. But over time, many people find that sticking to a diet this low in carbohydrate becomes impossible.”

    It isn’t impossible, and it also isn’t a done deal. It isn’t an all or nothing situation.
    By this I mean that it is also possible to take breaks from this regime.
    I found personally that taking breaks from low carbing only served to remind me why I was doing it in the first place.
    My glucose would spike wildly again. I’d feel exhausted, and suddenly the scoop of icecream wasn’t as tempting as before. It represented problems.

    When something truly works as this does for me, I feel it’s simply a matter of time before you psychologically reprogram yourself to appreciate it, and therefore enjoy it and those foods surrounding it almost no matter what they are.
    It can just take a little patience to find what you like to eat among the narrower field of choice.

  • bd

    You’re meant to replace the bulk of your diet with low carb foods and proteins, not just stop when you hit the very low levels of carbs.
    Therefore you wouldn’t eat the apple at all.
    The salad would be okay providing you chose your dressing wisely.
    An egg would be counted as 1 carb per.
    The use of fats is more allowable now.

    I personally keep things to easy to digest proteins, and bolster the carbs if needed with wasa crackers and very low carb leafy green vegetables.

    You’ll find that generally the trace amounts of carbs in proteins are enough for the most part, and the wasa crackers help you to stay regular on a diet that is a little more difficult to digest than a more conventional one.
    Calorie intake isn’t an issue, trust me.

  • Christine, Ireland

    Can anybody tell me how to convert 140milligrams per decifer to the european reading system where 5 seems to be good.
    I followed atkins when recently diagnosed but changed to GI and readings are between 9 and 13 now. thanks

  • Diane Fennell

    Hi Christine,

    Thanks for your question. Milligrams per deciliter (mg/dl) can be converted to millimoles per liter (mmol/L) using an online blood glucose converter such as the one found here:

    According to this tool, 140 mg/dl is equal to 7.8 mmol/L.

    Diane Fennell
    Web Editor

  • David Spero RN

    Dear Christine,

    Divide mg/dl by 18 and you get the European value, which is expressed in mmol/l. To convert European/Canadian to USA values, multiply by 18.

  • h

    I tried pretty much a zero carb diet as a type 1 diabetic but found it had dangerous results. After 5 days I got ketoacidosis when my body started breaking down fat. I was finding the diet very easy until then. Very quickly I had heart palpitations, my blood sugar levels went up and my hear was pounding, confusion etc. I have been in A&E as a result of this (from am broken insulin pump not no carb diet) and was told I was close to a cardiac arrest. It is very scary to think that doing a diet like this can do the same thing. To get round it I had more insulin and drank lots and ate a bowl of cereal. Quite disappointed :-(

  • will ragsdale

    I just can’t force myself to go to the doctor. It’s a psychological defect I guess.
    Anyway, I’ve been not so well for the past 2 years, and all the symptoms indicate (possibly type 1) diabetes. So I got a glucose meter, and sitting with my son on the couch, was horrified to find my glucose level was too high to measure, over 600 mg/dl!
    My son looked worried and said “Dad, you better go to the doctor!” I explained that that would mean injecting insulin for the rest of my life. How about if I tried changing my diet, and if that did not reduce the glucose level, I would go.
    I stopped eating all carbs. I eat a low calorie diet including fats and fiber and greens and small quantities of certain nuts. In one week, blood sugar was down to 199. By two weeks (admittedly with the help of the ayurvedic antihyperglycemia herbal supplement Glucomap), it was down to 108 consistently. I will have to try not taking the supplement to find if it is truly effective or not.
    Yes I should go to the doctor to check cholesterol and heart health and so on. I don’t have a weight issue, and I exercise regularly, though not enough.

    • Steve Mcgee

      Please note that Type one diabetes is an autoimmune disorder. You cannot gradually develop ‘type 1 symptoms’. You either are, or you aren’t. I can tell you that if you were, you’d be dead within about 3-5 days of no insulin injections. It is true that occasionally, adults are diagnosed with type 1 diabetes, (very rare), it used to be called Juvenile diabetes because MOST that develop it, are children.

      Type 2 diabetes though; there can be a genetic component to it, but 90% of the time you give that to yourself by over eating and causing your body to not be able to ‘keep up with demand’ for insulin production, so eventually your body just slows down or stops producing.

      Honestly I really think they should be called two totally different names because the type 1’s don’t deserve the stigma that all the type 2’s bring with them; they were born with it.