More Evidence for Low-Carb Diets

In our book we point out a number of dietary tactics that appear to substantially decrease risk of cardiovascular disease. They include:

  • Optimizing tissue omega-6 to omega-3 balance by minimizing intake of omega-6 fats and eating an oily marine fish like salmon or sardines once a week.
  • Optimizing various micronutrients including vitamins D and K2, choline, magnesium, iodine, and selenium.
  • Reducing carbohydrate intake to the body’s natural level of glucose utilization, about 30% of total calories.

We cited two main sources for the claim that reducing carbohydrate intake reduces risk of cardiovascular disease:

–          The Nurses Health Study found that risk of coronary heart disease went down steadily as dietary carbohydrates were reduced and replaced by fat. Those eating a 59% carb diet were 42% more likely to have heart attacks than those eating a 37% carb diet. [1]

–          Replacing dietary carbohydrate with saturated or monounsaturated fat raises HDL and lowers triglycerides, changes that are associated with low rates of cardiovascular disease. Blood lipids are optimized when carb intake drops to 30% of energy or less. [2]

I think this is pretty strong evidence. It is not completely bulletproof, because associations don’t prove causation and improving risk factors doesn’t necessarily improve disease risk; but, combined with supportive evidence from cellular biology and clear evidence that evolutionary selection favors a carbohydrate intake around 30%, I consider it convincing.

However, it’s always good to have more evidence; and two new studies provide some. One directly relates utilization of carbohydrates for energy to atherosclerosis, and the other conducted a 12-month clinical trial of a carbohydrate restricted diet.

Carbohydrate Utilization is Associated With Atherosclerosis

Via Stephan Guyenet comes a study that directly links carbohydrate metabolism to atherosclerosis: “Metabolic fuel utilization and subclinical atherosclerosis in overweight/obese subjects.” [3]

The study used intima-media thickness in the carotid artery, which serves the head and neck, as a measure of atherosclerosis. As Wikipedia notes,

Since the 1990s, both small clinical and several larger scale pharmaceutical trials have used carotid artery IMT as a surrogate endpoint for evaluating the regression and/or progression of atherosclerotic cardiovascular disease. Many studies have documented the relation between the carotid IMT and the presence and severity of atherosclerosis.

To assess metabolism it measured the “respiratory quotient” or RQ. RQ is the ratio of carbon dioxide (CO2) generated in the body to oxygen (O2) consumed in the body.

RQ indicates which fuels are being burned for energy in the body. When carbohydrates are burned, the reaction involves carbon exclusively, so for every O2 molecule consumed there is a CO2 molecule created. This makes the RQ 1.0 when carbohydrates are burned.

Fats, however, donate both carbon and hydrogen, and the hydrogens react with oxygen to make water (H2O). So some of the oxygen consumed when fats are burned goes into water, not carbon dioxide, and the RQ when fats are burned is about 0.7. Ketones also have an RQ around 0.7.

Amino acids from protein have variable amounts of hydrogen and carbon, some amino acids are ketogenic and some are glucogenic, and so the RQ of protein depends on its amino acid mix. Typically RQ from different types of food protein is between 0.8 and 0.9.

However, most people eat a fairly consistent amount of protein, around 15% of energy, so the variable that generally determines RQ in practice is the ratio of carbs to fat in the diet. Higher RQ indicates a higher-carb diet.

Another study had previously shown that calorie restriction, which also reduces RQ by replacing dietary carbohydrate with fat released from adipose tissue, reduces the thickness of the carotid intima-media. [4] This study was the first testing whether the RQ-CIMT relationship holds also in subjects not known to be restricting calories.

The study found that indeed it does: the lower RQ, the less atherosclerosis the subjects had. Unfortunately they don’t present data in a visually useful way (a scatter plot of RQ vs CIMT would have been helpful); here is what they do show:

RQ was better than waist circumference or BMI at predicting degree of atherosclerosis. Only age was a stronger predictor of atherosclerosis than RQ.

RQ predicted atherosclerosis equally well in subjects with and without obesity. This tells us two things:

  1. It supports the idea that it was habitual diet rather than recent calorie restriction (which decreases RQ by replacing food-sourced calories with fat from adipose tissue) that generated low RQ and low CIMT.
  2. As the authors say, it indicates “the main role of metabolic factors rather than BMI” in generating atherosclerosis – metabolic factors meaning burning glucose for energy rather than fat.

It is also supporting evidence for one of the more controversial lines of our book, that “mitochondria prefer fat.”

One caution: Most of the subjects in this study were eating diets that were around 50% to 55% carbohydrate, so the study was testing whether it’s better to eat a little above or below this carb intake. It tells us, I think, that a 45% carb diet is healthier than a diet with more than 50% carbs. It doesn’t tell us what carb intake is optimal.

The Clinical Trial

In a trial lasting 12 months, restricting carbohydrates to 600 to 850 calories per day – that is, about the 30% of energy that we recommend – in the context of a slightly hypocaloric diet improved cardiovascular risk factors. [5]

Overweight and obese subjects in the trial lost 2.8 kg (6 pounds) over the year-long trial, so it couldn’t have been severely calorie restricted. Changes in other risk factors:

–          Blood pressure dropped from 121/79 to 112/72;

–          Fasting blood glucose dropped from prediabetic 106 mg/dl to normal 96 mg/dl;

–          Lipids improved, with triglycerides decreasing from 217 to 155 mg/dl and HDL increasing from 39 to 45 mg/dl.

They conclude:

The results of this study indicate that a moderately restricted calorie and carbohydrate diet has a positive effect on body weight loss and improves the elements of metabolic syndrome in patients with overweight or obesity and prediabetes. These results underscore the need to provide dietary recommendations focusing on calorie and carbohydrate restrictions … Our results are in agreement with reports produced by other authors who also assessed a carbohydrate-reduced diet …

Conclusion

A number of simple dietary and nutritional changes appear to reduce the risk of atherosclerosis and cardiovascular disease generally. One of them is reducing carbohydrate intake.

I believe the optimum carbohydrate intake is around 30% of energy. Many studies generate clear evidence of benefits as carbs are brought down into the range of 20% to 30% of energy, especially in metabolic disorders like metabolic syndrome, diabetes, and obesity. It’s good to see that evidence from other diseases, such as CVD, also supports the same carb intake.

Because most people’s diets are flawed in so many different ways, and fixing an individual factor is often associated with a reduction in CVD risk of 40% to 70%, it’s possible that we could reduce CVD risk by 90% or more by implementing all of the dietary optimizations described in our book.

It’s well worth pursuing all these little optimizations!

References

[1] Halton TL et al. Low-carbohydrate-diet score and the risk of coronary heart disease in women.  N Engl J Med. 2006 Nov 9;355(19):1991-2002. http://pmid.us/17093250.

[2] Krauss RM. Atherogenic lipoprotein phenotype and diet-gene interactions. J Nutr. 2001 Feb;131(2):340S-3S. http://pmid.us/11160558.

[3] Montalcini T et al. Metabolic fuel utilization and subclinical atherosclerosis in overweight/obese subjects. Endocrine. 2012 Nov 28. [Epub ahead of print] http://pmid.us/23188694.

[4] Iannuzzi A et al. Comparison of two diets of varying glycemic index on carotid subclinical atherosclerosis in obese children. Heart Vessels. 2009 Nov;24(6):419-24. http://pmid.us/20108073.

[5] Velázquez-López L et al. Low calorie and carbohydrate diet: to improve the cardiovascular risk indicators in overweight or obese adults with prediabetes. Endocrine. 2012 Sep 1. [Epub ahead of print] http://pmid.us/22941424.

Leave a comment ?

48 Comments.

  1. Hi Paul,

    I look forward to reading your new edition soon. I took a gander at the clinical trial paper that you referenced and found it interesting that investigators spent a lot of time educating the subjects on how to eat a healthier diet. They also had them exercise three times a week for 30 minutes.

    It seems to me that the subjects consumed a much more nutrient dense diet given they were instructed to consume 25 grams or more of fiber. That would be indicative of more fruits, vegetables, and other plant foods. Interestingly, four to five rations of cereals were recommended as well. The subjects reduced their carb ratio to 50% and as a result ate more meat/dairy in their diet. Again, more nutrition provided as well from the animal products.

    However, can we really say that it was the carb reduction that improved blood pressure and lipid markers?

    It seems to me that there are a lot of variables at play in this study. Like the Perfect health diet, it is so nutrient dense that perhaps carb reduction may not be as important since carbs are coming from nutrient dense whole foods.

    Hope all is well.

  2. They mentioned that the diets were from 1200-1700 calories, and that is probably a significant reduction for obese subjects. There was no control group, so we can’t really say that the reduction in carbohydrates was the main cause of the improvements, at least definitively. That they didn’t lose tons of weight might mean that they were actually eating more than they were supposed to, but they were clearly in negative energy balance, which can reduce metabolic syndrome in its own right by combating nutrient overload. The authors acknowledged that.

    It could be other dietary advice like their suggestion to include at least 25g of fiber per day, or just the fact that they were on some sort of a diet and being more conscientious about what they ate. But I suppose it does support the idea, just not very strongly.

    However I don’t need this trial to tell me that low carbohydrate dieting produces those changes, there are plenty of others that do and demonstrate it better. 😛

    Where I really agree with PHD carbohydrate recommendations is in the optimal amounts of fats and proteins and the minimum for carbohydrates in my view. 40% fats minimum for mood, maybe I’ll be safe and go to 50%, at least 20 for muscle repair, and so 30% carbs by energy works. Couple that with the evolutionary rationale and I think I’m sold.

    As for the first study, even if we acknowledge that it is likely that less carbohydrates means less hyperglycemia and less atherosclerosis, that relationship is dependent upon so many variables that I’m hesitant to say that carbohydrates cause atherosclerosis. There is other weak evidence like this paper http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2943062/ but it could all be refined carbohydrates, or it could be defective carbohydrate metabolism which is easily avoidable. Although not as easily reversible so I can see how it might be wise for unhealthy people looking to a diet book to tell them how to avoid death to side with less carbohydrates.

  3. Hi Paul,
    Thanks for another great informative post! I am so grateful for the education I receive from your site and other great sites like this one.

    Not sure if I understood correctly, but in your sentence below (just a little below the fig. 1 on RQ) didn’t you mean to say “…(which DECREASES RQ…)? Or did I misunderstand?

    “It supports the idea that it was habitual diet rather than recent calorie restriction (which increases RQ by replacing food-sourced calories with fat from adipose tissue) that generated low RQ and low CIMT.”

    KH

  4. Overeating raises RQ. It would seem that excess caloric intake is what may be the driver here. It is amazing when calories are controlled properly and subjects eat enough to maintain or slightly lose weight how much of their metabolic problems tend to clear up. So, if the diets weren’t properly controlled calorically there is not much you could glean from it. If you look hard enough I bet there are studies of humans or other animals that maintain an RQ of around 7 even on “high carbohydrate” diets though I’ve never looked myself.

    • Hi Gabriel,

      Overeating per se doesn’t raise RQ; that only happens if it shifts energy utilization from fat to carbs. Which overeating will on high-carb diets, since we have unlimited fat storage but limited glucose storage, so the excess fat can be stored but the excess glucose has to be burned.

      But if the carb and protein fraction of the diet is low enough, overeating won’t raise RQ.

      • Many people and animals can maintain low fasting RQs even on high carbohydrate diets though. A trait of the metabolically unhealthy seems to be that they are “stuck” at a certain RQ, where they can’t oxidize enough glucose after eating it and can’t oxidize enough fat otherwise.

        • Hi John,

          Yes, that’s a great point. That’s basically the way the authors are inclined to interpret the study — that it results from mitochondrial / cellular metabolic dysfunction.

          But the subjects did not have any chronic illness, including diabetes, so it’s not clear how metabolically unhealthy they were.

          We know that high carb diets tend to make fasting less tolerable and lead to lower fasting blood glucose — eg the Kitavans have fasting blood glucose in the 60s — while low-carb diets make fasting easier and maintain blood glucose levels through the fast. So I think it’s clear that the disposition of cells/mitochondria to utilize glucose lasts longer than an overnight fast.

          Needs more study to clarify the issue I guess.

  5. Hi Paul.

    Would sleep deficiency (and some other stresses) raise RQ too, by decreasing fat metabolism and increasing carb metabolism?

    http://www.drbriffa.com/2011/08/02/disrupted-sleep-can-stop-you-burning-fat/

    “In moving from uninterrupted to interrupted sleep, carbohydrate metabolism went up from an average 324 to 346 grams/day (statistically significant).

    At the same time, fat metabolism dropped from 61 to 29 grams per day.”

  6. I came away wondering if 30% carb just might be therapeutic for metabolic disorders and what does it tell us about maintenance carb consumption of more generally healthy folks.

    • Hi Mark,

      I think diets need to be robust and so shouldn’t challenge the body in ways it may potentially fail at.

    • Is 30% the optimal level of carbs to keep LDL at the lowest and HDL at the highest values?

      So, does the level of carbs drive LDL receptors, or iodine, or ????

      • Hi Evan,

        I would say that 30% carbs will tend to normalize LDL. Lower carb intake will tend to drive it higher than optimal and higher carb intake will tend to drive it lower than optimal. However, many other factors influence LDL levels, including iodine, thyroid hormone, selenium, copper, etc.

  7. > Blood pressure dropped from 121/79 to 112/72;

    The starting figures seem surprisingly low for a set of overweight and obese patients.

    Also, the ending figures don’t necessarily seem like an improvement. When my blood pressure gets below 110/70, I begin to get sluggish and have trouble staying awake. I’ve heard this from a number of other people too. Looking at the study’s abstract, the systolic fell to 112.4 with a standard deviation of 11.5, and the diastolic to 71.8 with a standard deviation of 8.3, which would mean that perhaps 40% of the subjects might have developed excessively low blood pressure.

  8. Interesting post Paul,

    It’s important to remember that the first study cited was still correlative. It could be that the people who had the highest CHO intake also ate the most calories.

    The second study supports the idea that calorie restriction improves cardiometabolic risk factors, but neither directly support the idea that reducing carbs per say will do the same.

    It’s also important to remember that what’s true for obese or overweight people is not necessarily optimal for lean healthy people.

    When you say that the “optimal CHO intake is around 30%” are you assuming that the person in question is sedentary?

    Thanks for the post and providing references, 🙂

    – Armi

    • Hi Armi,

      For exercisers/athletes it depends on the nature of the exercise, intense exercise may raise CHO utilization to 40% and low level endurance exercise like hiking could in principle lower the CHO percentage by increasing fat utilization but not carb utilization.

      I think 30% is a pretty good ballpark figure.

      • Excellent article.

        What is the optimal way to limit carb intake to between 20% and 30% of our diet?”

        • Hi Shameer,

          You will find all the information you need in the PHD book.I will receive my pre-ordered copy of the new version in a couple of days. I already own the first version. It’s a wonderful book.

  9. Will the book be available in a kindle edition?

    • Hi Katy,

      It’s available now in the US and Canada in all ebook formats. The Australia/NZ/UK rights have been sold and there will be an Australia/NZ Kindle edition released Jan 7, I’m not sure when a UK edition will be released.

  10. I’ve just been diagnosed with high blood pressure so I’m going to try reducing carbs in my diet. I’ll let you know how I get on.

  11. Hello,

    I’ve been a follower of lower-carb diet, or more precisely Paleo diet for a while now. Undoubtedly this works for me as a weight control diet. I am also following the Big Five fitness programme.

    Anyway my comment is about atherosclerosis. Some genetic predisposition seem to be running on my father’s family side as all male are affected by it.

    So my reason for following a paleo style diet is partly because of this: reducing carb intake to lower insulin response and all side effects.

    I’ve recently read a study about the increase of atherosclerosis in Low carb diets: it is here: http://news.harvard.edu/gazette/story/2009/08/low-carb-diets-linked-to-atherosclerosis-and-impaired-blood-vessel-growth/

    What do you think of it?

    • Hi Vincent,

      I recall looking at that study a few years ago. Here it is: http://www.ncbi.nlm.nih.gov/pubmed/19706393. Their “low-carb diet” is 45% protein which is a toxic level of protein. It is a purified nutrient diet of casein, sucrose, cornstarch, and milkfat plus vitamins and minerals; you always wonder about nutrient deficiencies, especially choline. High protein inhibits appetite and they may have been undereating which would be consistent with the lower weight gain of the low-carb high-protein mice. The mice in question were ApoE knockout mice and this is a very important molecule which is diet sensitive. Their measure of changes to # of EPCs was insignificant at every week except at week 5, where it was barely significant.

      It is hard to interpret small relatively brief studies in genetically altered mice using peculiar diets that don’t resemble anything a human would eat.

  12. Hello,

    I’ve been reading the new edition of the book and posts here at the website. I’m looking at doing the ketogenic diet and was wondering about butter and other saturated fats. Do I need to cut back on them during the intermittent fast? If my bone broth has fat on top, do I need to skim it?

    I usually require digestive enzymes for everything. I’ve been taking MCT oil in smaller doses for a while. It tends to burn. This morning I took 2 tablespoons with a cup of fatty bone broth and an ox bile–no burning. But maybe it’s not optimal to need a supplement during the fast part.

    If meat, including bacon, tastes bad, does that mean I don’t have to worry about it for a while? I usually douse with mustard. The bacon tasting bad though really threw me off.

    Aside from questions, I just wanted to say that I’m wildly impressed by your book and website. I’ve seen you say things that I heard first from ND’s and other alternative practitioners. But their tone was what I’d expect from a humanities major who barely scraped by in a biology class. So thanks for being out there, and going on shows like Underground Wellness.

    • Hi Crystie,

      If you’re trying to lose weight then you shouldn’t eat butter during the fast, but if you merely want to generate ketones then it’s fine.

      I don’t see anything wrong with bone broth and ox bile alongside MCT oil.

      I’m not sure what you mean about bacon tasting bad. There’s no obligation to eat bacon. You should find foods you like.

  13. Paul,

    Thanks for the quick answer! I’m looking at the ketogenic diet because I have gut problems, anxiety, depression, and I don’t like leaving the house. I have food sensitivities and have been grain free (except for eating out once a week) for 9 months. Most of my food is from scratch. I have a range of symptoms when I transgress. The one that gets me the most though is this sense of inexplicable, low-grade pain through my insides that I can’t pinpoint. I decided it must be systemic nerves. It’s a bit like the pain I experience in the skin of my legs that I didn’t realize was driving me crazy until I put tallow on it and it completely subsided.

    Tallow is amazing stuff.

    By my bacon comment, I meant that sometimes I have times where almost all meat tastes rotten to me. This week it’s all meat, since bacon came up as a miss for the first time.

  14. Worth viewing for a good laugh. 9 out of 10 doctors recommend eating a bowl this daily to reduce heart disease. http://www.youtube.com/watch?feature=player_embedded&v=UVrJN3kHpJA Brought to you by Medifacts. Medical fact I think not. 🙂

  15. Hi Paul:
    I heard that losing hair on toes and one’s lower legs according to Dr. Oz is a sign of cardiovascular disease??!!!!

    Ever since I went on the Paleo diet two years ago, I have noticed that there is no more hair on the top of my hands, not as much on my arms, and none left on my toes, and lower legs.
    Paul, I am greatly concerned about this!

    I am wondering, could some of the reasons be due to the fact it could be the consumption of meat, coconut butter, and other ‘fats’ which you say are good for you, however, may have been comprising my health??

    Further, my ankles are routinely swollen after the end of a working day, and it appears that I also have edema, yet my doctor when examining me does not think I have edema.

    Paul, is it possible as some posts have suggested, that perhaps one should limit red meat, and incorporate qunioa for example, even though you are not high on carb intake, to help with potential cardiovascular disease.

    I do not smoke, am middle aged, and exercise regularly, yet recently have experienced all these problems, which is causing me great anxiety.
    Your thoughts are appreciated Paul.
    Thanks Paul!

    • Hi Lawrence,

      Hair loss is usually a sign of hypothyroidism, it can also be a symptom of deficiencies such as iron deficiency or of infections. Hypothyroidism is a major cause of cardiovascular disease so I can believe there is an association, but I am not aware of a causal connection between the vasculature and hair loss.

      Swollen ankles suggest kidney/adrenal dysfunction and/or electrolyte disturbances — either too much or too little. Adrenal issues commonly coincide with thyroid issues.

      I would suggest normalizing your supplementation and food intake toward moderate levels. In particular:
      – Make sure you are eating ~30% carbs and adequate protein, therefore not an excess of fats.
      – Try to get most fats from nourishing foods, rather than from oils, so that you get adequate phospholipids, fat-associated vitamins, and other nutrients.
      – If you are taking high iodine or selenium, reduce the dose. Try 225 mcg/day iodine and 200 mcg/week selenium.
      – If you are taking a lot of magnesium, try reducing it – no more than 200 mg/day, 100 mg/day may be enough.
      – Get enough potassium by eating tomatoes and potatoes.
      – Get adequate salt — try to put a bit more salt on your foods.
      – Get enough calcium via bone broth.

      At your doctor, ask for thyroid and lipid tests.

      Have you read the most recent edition of our book? Does you diet correspond to our food plate?

  16. Paleo Breakfast Muffins Recipe - pingback on March 8, 2013 at 9:27 pm
  17. Hi Paul:
    I came across this magazine article,
    http://commonground.ca/2013/02/the-real-paleo-diet/
    and the author states according to the ‘United States News and World Report’, that the Paleo diet was one of the worst diets
    that one could consume.
    Paul, what is your opinion on this article?

    Secondly, upon receiving my blood tests results from my most recent annual physical, my Doctor stated that the LDL cholesterol was a little high, and the ECG showed an incomplete right branch block?!! (Although the internet said that a right block is not all that serious, just something that needs to be checked once a year or so.)

    So I ask you Paul, is the evidence really there for a ‘low carb diet?

    I still think Paleo is the way to go, however, with my cholesterol reading being a little high, and circuitry concerns with the heart, it makes me think is this diet for real, and or should one bend a little with the hunters gatherers diet to suit their individual needs?

    Your thoughts?
    Thanks Paul!

    • Hi Lawrence,

      How low-carb are you? I think the evidence supports eating a 30% carb diet.

      I agree with some of what that lady says, not all. Paleolithic people certainly consumed a great deal more salt than she says. She is right that their diet was 2/3 – 3/4 plant foods by weight (but so is PHD), and that we should eat offal and bone soups (as PHD recommends). The idea that if we can’t get wild game, we should replace it with soybeans, is absurd.

      For high cholesterol see our “High LDL on Paleo” series. It commonly indicates a diet that is too low in carbs.

  18. How to Prevent Kidney Stones Naturally - pingback on September 27, 2013 at 1:25 pm
  19. Hello,

    I have really enjoyed the work you do.

    I saw this article today and I don’t believe that you’ve cited it anywhere, so I thought I’d bring it to your attention. It’s a one year old meta-analysis of the dangers of low-carb diets.

    http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0055030

    Best,
    Craig

  20. Hi Paul:

    I’ve been following a low carb diet for the past couple of years; my ldl went from 88 on a high carb diet to about 240. After reading your blog and buying your book I decided to add some carbs, and supplement with 350mcg of iodine in the am 350mcg at night, and a couple of months later my
    ldl comes down to 130, but around 6 months later my ldl was 198, hdl 120, trig 50. I had also a PLac test, lp-pla2, that came very high at 265 and c-reactive protein at 0.38. I have read that an HDL higher than 100 gives false positives for Lp-pla2. Also, I am APO E3/4. My doctor recommended a diet low in sat fat, although I eat nuts, and almond butter, almond milk, and she recommended 1 tbsp of olive and 1 of coconut oil daily. Now, I’m trying to avoid added fats as much as possible, and my protein intake is under 20%, and I don’t want to overdo carbs as I am at risk for diabetes, (no family history, no obesity, in fact I’m a long distance runner, 57 yr. old female) so the bottom line is that I’m hungry, I miss fats, and I’m unhappy with my current diet. What is your opinion on coconut oil and the APOE3/4 genotype? The research I’ve come accross on the internet is very scant and most of it points to a very low fat diet, almost vegan, without giving specifics on sat fat, mono or poly fats.

    I’m curious to hear your response…

  21. Sometimes it's difficult to know what to think when "reliable sources" about diet and nutrition seem to disagree with a way of eating that you have found valuable. Are there hidden dangers to low-carb eating? Should you be worried? What if you aren't eating what the government guidelines tell you to eat?

  22. I was amazed to see that poultry has such high levels of omega 6! My concern is the recommendation for having so much red meat. If one is at risk of stomach cancer, should you have that much red meat? My understanding is that studies show an increase in stomach and colon cancer with having to much red meat and pickled products which are both recommended in this diet.

  23. After reading the book, I have a question concerning the amount of carbohydrates to meet the 600 calorie mark. The background of my question stems from the below excerpts from the book:

    At the bottom of page 100, it says “So four fist-sized servings per day of safe starches-one or two per meal-is the proper quantity of safe starches.” On page 102 is sums it up by saying to “Combine 1 pound per day of safe starches such as white rice, white potato, winter squashes, taro, or sweet potato, with 1 pound per day of sugary plant foods, such as beets or fruits and berries.” “A pound of sugary plants equals about three beets, three bananas, or three large peaches per day.”

    For simplicity sake, lets say I ate 4 fist sized sweet potatoes and three bananas a day. So, accordingly to the labels, a small sweet potato has ~25g carbohydrate and a banana ~30g carbohydrate. So, at the quantity I’m eating them that’s 100g carbohydrate from the sweet potato and another 90g carbohydrate from the bananas thereby totaling 190g X 4 = 760 carbohydrate calories.

    I am I overlooking something? I have been following PHD for about three weeks and really like it, however I only eat 2 sweet potatoes, a banana (which brings me to 80g CHO) and I find the rest of my CHO is made up of nuts, carrot, sugar in full fat greek yogurt, etc.

  24. Paul,

    Thank you for the prompt response. I hadn’t accounted for the fiber content, which of course makes a difference. I was using an “APP” on my smartphone I’ve been using to track calories until I get used to the proper amounts to eat. It put bananas slightly higher, but as you said it’s just an estimate.

    As a followup, I know we are to disregard the CHO content of non-starchy vegetables, but do you count CHO from Greek yogurt or other dairy products?

  25. Anonymous - pingback on September 12, 2014 at 4:33 pm

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