My Big Fat Diet FAQs

1. What is a carbohydrate?

We get our energy from the food we eat in the form of calories from protein, fat and carbohydrate (also alcohol). Foods from plant and animal sources provide protein and fat. Carbohydrates, however, come exclusively from plant sources. We commonly refer to carbohydrates as starch and sugar. Any food that contains starch or sugar, whether it is natural or refined, is a source of dietary carbohydrate. For example, a glass of fruit juice is rich in fructose, a natural sugar, while a can of pop will have sucrose, a refined sugar that has been added, but in both cases the carbohydrate content is about the same. Other common carbohydrate foods include fruit, starchy vegetables like potato and rice, anything made with flour including bread, pasta and pastries, anything that contains sugar and milk which contains lactose, a naturally occurring sugar. All these foods, once they enter our digestive system, will produce a rise in blood glucose.

2. Doesn’t our body need carbohydrates?

No. This is a common myth. For instance, many people, even medical professionals, will tell you that the brain needs glucose (from carbohydrates) to function. In fact, the brain can get up to 80% of its energy needs from ketones, an energy source produced from fat in our liver. There are a few tissues that do require exclusively glucose for their energy needs like the lens of the eye, the red blood cells and a part of the kidney. The fact is that the liver is capable of producing sufficient glucose to sustain these tissues through a process called ‘gluconeogenesis’. All other tissues of the body are quite happy to burn fat or ketones for their energy needs when glucose is absent.

3. Aren’t ketones supposed to be harmful?

We all produce ketones from time to time when our supply of dietary carbohydrates dwindles. Many people will produce them in the early hours of the morning after the carbohydrates they ate for dinner are used up. People on a low-carbohydrate diet will burn ketones along with fat for most of their energy needs. We sometimes test the urine of low-carb dieters to measure ketones to determine if the diet is working. The levels of ketones in the blood in all these instances is not high enough to cause any harm. There is a condition known as ‘ketoacidosis’ which is harmful and part of the confusion around ketones may be due to this. Ketoacidosis is a serious problem that occurs in type 1 diabetics when they are not given insulin. In this case the ketone levels are many times higher and blood sugars are very high, too. While ketoacidosis is harmful, the ketosis experienced by low-carb dieters is not.

4. Will a low-carb diet increase my risk of heart disease?

This is another common myth. It is based on the notion that if you eliminate carbs as an energy source you will have to increase fat intake to compensate (there is a limit to how much protein you can eat). It was thought that an increase in fat would lead to high cholesterol which is associated with heart disease. When the studies were actually done on this, however, much to everyone’s surprise, the opposite happened. People on a low-carb diet improved their cholesterol readings even when they increased their fat intake and even when their intake of saturated fat (the so-called bad fat) increased. It appears that when you body must rely on fat for energy, the saturated fat you eat gets burned up before it can cause any harm. Another factor that plays a role in heart disease is the level of inflammation in our system. If the markers of inflammation are high we recognize this as a sign of increased risk of heart disease. We commonly order a C-reactive protein test, a marker of inflammation in the blood, to assess a person’s risk. A recent study showed that people on a low-carb diet demonstrated significantly reduced inflammatory markers.

Although there haven’t been any long term studies yet to prove it, the existing science suggests that a low-carb high-fat diet may actually reduce the risk of heart disease.

5. Will a low-carb diet harm my kidneys?

Many people mistakenly refer to low-carb diets as high-protein and we know that eating too much protein, if you have kidney damage, will worsen this problem. In fact, low-carb dieters tend to only moderately increase their protein intake and the scientific literature is clear that an increase in protein when your kidneys are healthy causes no harm. Dr. Mary Vernon, a Kansas physician who specializes in treating diabetics with a low-carb diet, has reported that patients who have very early signs of kidney damage from their diabetes can actually correct this problem with a low-carb diet, something that has not been demonstrated with any drug or other type of therapy.

The bottom line is that if you have documented kidney damage, you should not make a big dietary change without consulting your doctor. For everyone else, there is no need to worry about kidney damage from a low-carb diet.

6. Does a low-carb diet increase the risk of gall stones?

Gall stones develop when the gall bladder is inactive. Once they have developed, there is a risk that contraction of the gall bladder will cause a stone to block the gall duct. This will lead to an acute gall bladder attack which can be very painful. When gall stones are diagnosed, usually by ultrasound, surgery to remove the gall bladder is generally regarded as the best way to correct the problem. The gall bladder tends to contract in response to a fatty meal. If someone has gall stones and they eat a fatty meal this could trigger an acute gall bladder attack. On a low-carb diet, most of the calories come from fat but, initially this is the fat that the person has stored. Burning off stored fat won’t trigger a gall bladder attack. Later on in a low-carb diet, when weight loss has reached a plateau, increasing dietary fat could theoretically trigger a gall bladder attack. There have been no reports of this in the literature and my colleagues who have had years of experience in guiding people on low-carb diets tell me that the risk is no greater than if people were eating a regular diet.

7. Why do all the authorities on diet advise against a low-carb diet?

This is a hard question to answer in a few words. My friend Gary Taubes, the acclaimed American science writer, has authored a 460 page book which answers this question. I highly recommend “Good calories, Bad calories” to anyone interested in gaining a better understanding of what is wrong with the current nutritional approach. In short, the current recommendation to eat a majority of our calories as carbohydrates reflects the conventional wisdom that dietary fat is the cause of heart disease. Since there is a limit to how much of our daily energy needs can be obtained from protein, we are left to chose between carbs and fat. If you believe fat is harmful, then you are left with carbs as the main source of energy. As Gary documents in his excellent book, the science implicating fat in heart disease is not particularly sound. It may, in fact, be that carbs are the dietary villain, not fat. There have been a number of recent studies that have shown that people on a very low carb diet can eat lots of fat, including saturated fat, and achieve a better lipid profile than people eating the American Heart Association recommended low-fat diet. In a recent editorial, Dr. Frank Hu, a well-respected Harvard nutritional researcher, argued that, based on the evidence, public health programs to reduce cardiovascular disease need to shift from targeting dietary fat to targeting carbohydrates. He states that the original programs to discourage fat consumption may have backfired and inadvertently increased obesity and cardiovascular disease by encouraging a shift towards carbohydrate consumption.

9 thoughts on “My Big Fat Diet FAQs

  1. Pingback: My Big Fat Diet

  2. Is there a book or plan you would recommend to start out with? How often a day do you recommend testing with this diet? I’m currently on metaformin, levemir, and novolog and I want to get off them. I’ve always had trouble with blood sugar. When I was younger it was just low blood sugar, and now its type two diabetes. I’d like to present this to my doctor, and I would love your advice on how to best go about it.

    Dr Jay’s Reply:

    I currently recommend “The Art and Science of Low Carbohydrate Living” by Volek and Phinney. It was originally intended for physicians but is accessible to the general population.

    If you are currently testing and adjusting insulin, it is recommended that you should do it at least two or three times a day as you cut the carbs. A general rule of thumb is to reduce dosages by half beginning on the first day. It’s best to do this under the supervision of your doctor, of course.

  3. Dr. Jay I go in on the 20th. I will look up that book and talk to my doctor. Thank you.

  4. I’ve always been leary about a low-carb diet because of the production of ketones and the risk for ketoacidosis. Previous versions of the Atkins diet alway recommend inducing this state. Are there ways to limit this complication. I’m a type 2 diabetic who’s about 120lbs. overweight. My mother’s side of the family can trace it’s roots in canada to 1672, so there is a very good chance of me having a first nation’s genetic make-up.

    Dr Jay’s Reply:

    I think you are confusing ketosis and ketoacidosis. Ketosis means you have measurable ketones in your blood. This happens when you reduce your carbohydrate intake to the point where you are not getting enough glucose to fuel your brain. When this happens your liver starts producing ketones from fat to fuel the brain. The brain may actually prefer ketones and appears to run more efficiently on them compared to when it burns glucose. There is no harm in being in ketosis.

    On the other hand, ketoacidosis is harmful. This happens when you are unable to produce insulin. Insulin acts as a brake on ketone production in the liver. When you have no insulin, ketone production runs wild and the ketone levels in your blood get very high, much higher than when you are in simple ketosis. Other things happen at the same time: blood glucose levels get very high and you get dehydrated and acidotic. People with this condition are very ill and can die if not treated with insulin and fluids. Ketoacidosis is very rare in type 2 diabetics because they usually have high insulin levels rather than low. Ketoacidosis can be a problem for type 1 diabetics since they cannot produce insulin.

    Bottom line: don’t fear ketoacidosis if you are a type 2 diabetic.

  5. Dr. Jay,
    I have a daughter who very much needs to go high fat, low carb.
    But she had her gall bladder removed. I haven’t seen anyone comment on the effect of high fat diet on a person without a gall bladder.

    Thanks, Richard Kirby

    Dr Jay’s Reply:

    The gall bladder stores bile and when you eat a fatty meal, the bladder contracts to inject the bile into the intestine so you can digest and absorb the fat. Ironically, a low-fat diet can cause sludging of the bile due to inactivity of the gall bladder and eventually gall stones. There have been documented cases of gall stones forming during a low-fat weight-loss diet. Once the gall bladder is removed, the digestion and absorption of dietary fat may be impaired. In my experience, people who have no gall bladder can still do a low-carb diet. They have to proceed cautiously with ramping up the fat. For some reason, different kinds of fats may be more tolerated than others. I have heard people tell me that they can eat butter but not olive oil, for example. I suspect there is a lot of individual variation in terms of how much fat and which types are tolerated. I wouldn’t discourage your daughter from trying a low-carb diet with these caveats.


    Came across this and thought there might be some interest.
    Starving cancer with Ketogenic diet.

    Dr Jay’s Reply:

    Dr Eugene Fine and Dr Thomas Seyfried have been working on these concepts. I attended the lectures they gave at a recent meeting of the Nutrition and Metabolism Society. It’s an interesting approach that should bear fruit in terms of treatment options for cancer patients.

  7. Hi Dr. Jay,

    I was wondering if you could refer me to a dietician or nutritionist or naturopath – anyone who works with kids and can assist me with an alternative diet for my 6 year old T1 Diabetic son? I am extremely frustrated with Diabetes Clinic Dieticians who only promote high carb CDA sponsored diets. They frighten me with warnings about lows (he gets those now anyway) and about limiting carbs can affect his growth and development. There have got to be some different voices out there. I just haven’t found any. I’ve read Dr. Richard Bernstein’s book and he seems to be saying something very similar to you. Any advice would be appreciated. I don’t want to have to wait until my son is an adult for his blood sugars to be normalized. By then he’ll have had Diabetes for 15 years.

    Dr Jay’s Reply:

    I assume you are in British Columbia where, unfortunately, I don’t know of anyone who has expertise in managing T1 diabetes using low-carb. My own experience in this area is quite thin. I do think Dr. Bernstein is the best resource. I have heard him speak and he talks about the fact that the lower the insulin requirement, the lower the chance of hypos. In your case, I am sure you have been taught to use extra insulin to “cover” higher carb meals. If you are accustomed to raising insulin when carb intake is higher, you are also capable of lowering it when carb intake is lower. If you are comfortable doing this, it provides an avenue to get both the carbs and insulin down over time. I think that, just as it is the case with T2 diabetics, it is better to eat LCHF in terms of overall blood glucose management. Unlike T2’s, a T1 diabetic will always need insulin. The trick is to use a little as possible while attaining blood sugars in the normal range. I know this goes against the conventional thinking which, unfortunately, for the time being, means that you are on your own. Unless you can manage a trip to see Dr Bernstein.

  8. Hi Dr. Jay, How many carbs a day approximately do you eat? When counting carb.s do you do like Atkins net carbs ( # of carbs – fiber) or the total #? I can’t seem to get my A1c lower than 5.8 usually it’s around 5.9 or 6. I’m figuring I eat a total of about 50-75 carbs a day- good carbs ie;nuts,beans, veges,berries, greek yogurt, I piece Eziekle bread. Two and 1/2 yrs ago my A1c was 7.0 . I lost 35 pounds & lowered my A1c by watching carbs similar to Atkins, and lots of exercise. Also what’s your take on cinnamon and supplements like alpha lipoic acid,magnesium,vit. D,chromium, etc? My other catch is to lower my A1c without losing more weight. Any info. would be greatly appreciated.
    Thank you, Steve

  9. When are you coming back? It’s been over a year. You’re worrying your fans! Richard Steele, Douglas, Alaska

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