Tag Archives: low-carb

High-Protein Diets Harmful to Bones? Nah!

Contrary to accepted wisdom, high  protein intake does not seem to be harmful to mineralization of bone, according to Seattle-based researchers reporting in the American Journal of Clinical Nutriton.  Mineralization of bone is important because higher bone mineral content generally translates to lower risk of fractures.

A consistent criticism of low-carbohydrate diets in the past is that they are detrimental to bone health.  How so?  If you reduce carb consumption, you have to replace at least some of the calories with either fat or protein.  Some low-carb diets lean towards higher protein content, others towards higher fat, still others increase both fat and protein.  The building blocks of proteins are amino acids, and some amino acids are acidic.  Acid-rich biochemical states may promote removal of calcium from bone and, ultimately, loss of that calcium in urine.  The calcium-poor bones are more prone to fracture.

If that theory is correct, women eating greater amounts of protein should demonstrate lower bone mineralization.  [The primary bone minerals are calcium and phosphorus.] 

ResearchBlogging.orgInvestigators tested the theory in 560 women aged 14 to 40 by measuring bone mineral density (via DEXA scans) over two or three years and monitoring food consumption via yearly questionnaires.  This was an observational study, not interventional.

They found that bone mineral density had nothing to do with protein consumption.  Higher protein intake was not associated with lower bone density.

Women in the low-protein group ate 52 g of protein daily, compared to 63 g in the medium group and 77 g in the high-protein tertile.  As best I can tell, the low-protein third of participants ate 12% of total calories as protein, compared to 20% in the high-protein third.  [Study authors could have put this in the appropriate table, but, mysteriously, opted against that.]

Caveats

We can’t tell from this study whether these findings apply to protein intakes outside this range, to men, or to women older than 40.  To their credit, the study authors review much of the pertinent literature and note that research in this area produces results all over the map.  To me, this suggests that the association between dietary protein and bone mineralization in the general population is weak, if not nonexistent.

Bottom Line

Looks like you can stop worrying so much about hurting your bones if you’re on a low-carb, high-protein diet.

Steve Parker, M.D.

Reference: Beasley, J., Ichikawa, L., Ange, B., Spangler, L., LaCroix, A., Ott, S., & Scholes, D. (2010). Is protein intake associated with bone mineral density in young women? American Journal of Clinical Nutrition, 91 (5), 1311-1316 DOI: 10.3945/ajcn.2009.28728

 

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Drew Carey Succeeds With Very Low-Carb Diet

Jimmy Moore today at Livin’ La Vida Low Carb reports on Drew Carey’s fantastic success in losing 80 pounds (36.4 kg) of fat and controlling (curing?) his type 2 diabetes.  Jimmy says many Hollywood celebrities control their weight with carbohydrate-restricted eating.

Steve Parker, M.D.

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Diabetes Consumes 7% of the UK’s Drug Budget

The BBC reports that drugs for diabetes account for 7% of the United Kingdom’s National Health Service’s prescription drug budget. 

They would spend less on diabetic drugs if more diabetics adhered to low-carb eating or the Mediterranean diet.  Better yet, combine both eating styles as in the Low-Carb Mediterranean Diet.

Steve Parker, M.D.

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London’s Low-Carb Diet Fad of 1865

Dr. Robert Atkins didn’t invent low-carb dieting.  William Banting (1797-1878) sparked a low-carb diet craze in London with his low-carb weight-loss diet, first published in 1863.  Even that probaby wasn’t the first low-carb diet.

According to Wikipedia, Banting was a distant relative of Frederick Banting, the co-discoverer of insulin in 1921.

Mr. Banting attributes his successful program design to a “medical gentleman,” Mr. Harvey, of Soho Square, London. 

Click to read Mr. Banting’s 1865 “Letter on Corpulence” at Internet Archive.

Steve Parker, M.D.

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Book Review: Diabetes Solution – The Complete Guide to Achieving Normal Blood Sugars

Here’s my review of Dr. Bernstein’s Diabetes Solution: The Complete Guide to Achieving Normal Blood Sugars, published in 2007.  Per Amazon.com’s rating scale, I give it five stars (I love it).  

♦   ♦   ♦ 

Dr. Richard K. Bernstein gives away thousands of dollars’ worth of medical advice in this masterpiece, Diabetes Solution.  It’s a summation of his entire medical career and a gift to the diabetes community.  

The book starts off with some incredible testimonials: reversal of diabetic nerve damage, eye damage, and erectile dysfunction.  They’re a bit off-putting to a skeptic like me, like an infomercial.  Dr. Bernstein is either lying about these or he’s not; I believe him.  His strongest testimonial is his own.  He’s been a type 1 diabetic most of his life, having acquired the disease at a time when most type 1’s never saw 55 candles on a birthday cake.  He’s in his mid-70s now and still working vigorously.  

I only found one obvious error and assume it’s a misprint. He writes that 95% of people born today in the U.S. will eventually develop diabetes.  That’s preposterous.  The U.S. Centers for Disease Control predicts that one in three born in 2000 will be diagnosed.  

Dr. Bernstein delivers lots of facts that I can neither confirm nor refute.  He’s a full-time diabetologist; I am not.  

"Put down the bread and no one will get hurt!"

  

The central problem in type 1 diabetes is that, due to a lack of insulin,  ingested carbohydrates lead to spikes (elevations) in blood sugar.  The sugar elevations themselves are toxic.  The usual insulin injections are not good imitators of a healthy pancreas gland. So Dr. Bernstein is an advocate of low-carb eating (about 30 g daily compared to the usual American 250-300 g).  He says the available insulins CAN handle the glucose produced by a high-protein meal.  

Dr. B reminds us that insulin is the main fat-building hormone, which is one reason diabetics gain weight when they start insulin, and why type 2 diabetics with insulin resistance (and high blood insulin levels) are overweight and have trouble losing weight.  You can have resistance to insulin’s blood sugar lowering action yet no resistance to its fat-building (fat-storing) action.  Insulin also stimulates hunger, so insulin-resistant diabetics are often hungry.  

“Carbohydrate counting” is a popular method for determining a dose of injected insulin.  Dr. B says the gram counts on most foods are only a rough estimate—far too rough.  He minimizes the error by minimizing the input (ingested carbs).  From his days as an engineer, he notes “small inputs, small mistakes.”  

Dr. B also cites problems with the absorption of injected insulin.  Absorption is variable: the larger the dose, the greater the variability.  So don’t eat a lot of carbs that require a large insulin dose.  For adult type 1 diabetics, his recommended rapid-acting insulins doses are usually three to five units.  If a dose larger than seven units is needed, split it into different sites.  

He recommends diabetics aim for normal glucoses (90 mg/dl or less) almost all the time, and hemoglobin A1c of 5% or less.  This is extremely tight control, tighter than any expert panel recommends.  He says this is the best way to avoid the serious complications of diabetes.   

Here’s a smattering of “facts” in the book that made an impact on me, a physician practicing internal medicine for over two decades.  I want to remember them, incorporate into my practice, or research further to confirm:  

  • Hemoglobin A1c of 5% equals an average blood sugar of 100 mg/dl (5.56 mmol/l).  For each one % higher, average glucose is 40 mg/dl (2.22  mmol/l) higher.
  • He’s against any drugs that overstimulate (“burn out”) the remaining pancreas function in type 2 diabetics: sulfonylureas, meglitinides, “phenylalanine derivatives”.  Pancreas-provoking agents cause hypoglycemia and destroy beta cell function.
  • The insulin sensitizers are metformin and thiazolidinediones.  He likes these.
  • Blood sugar normalization in type 2 diabetes and early-stage type 1 can help restore beta cell function.
  • He often speaks of preserving beta cell function.
  • He believes in “insulin-mimetic agents” like alpha lipoic acid (especially R-ALA, and take biotin with either form) and evening primrose oil.  These  are no substitute for insulin injections but allow for lower insulin doses.  ALA and evening primrose oil don’t promote fat storage like insulin does.
  • He says many cardiologists take ALA for its antioxidant properties [news to me]
  • He says rosiglitazone works within two hours [news to me] but later admits it may take 12 weeks to see maximal benefit
  • One of his goals is to preserve beta cell function if at all possible
  • He prefers rosiglitazone over pioglitazone due to fewer drug interactions
  • “Americans are fat largely because of sugar, starches, and other high-carbohydrate foods.”
  • He’s convinced that people who crave carbohydrates have inherited the problem, which also predisposes to insulin resistance and type 2 diabetes.  Low-carb diets decrease the cravings for many, in his experience.
  • In small amounts, alcohol is relatively harmless: dry wine, beer, spirits.  Very few doctors have the courage to say this.
  • If you’re in a restaurant, you can use urine sugar test strips and saliva to test for presence of sugar or flour in food
  • A rule of thumb: one gram of carbohydrate will raise blood sugar about 5 mg/dl (0.28  mmol/l) or less for most diabetic adults weighing 140 lb (64  kg) and about 2.5 mg/dl (0.139 mmol/l) in a 280-pounder (127  kg).  This must refer to type 1 diabetics or a type 2 with little residual pancreas beta cell function; variable degrees of insulin resistance and beta cell reserve in many type 2s would make this formula unreliable.
  • Be wary of maltodextrin in Splenda: it does raise blood sugar.
  • Much new to me in his section on artificial sweeteners.  Be wary of them.
  • He avoids all grains, breads, crackers, barley, oats, rice, and pasta.
  • Most diet sodas are OK.
  • Coffees with 1-2 tsp milk is OK.  Cream is OK.
  • He eats NO fruit and recommends against it.
  • He avoids beets, corn, potatoes, and beans. A slice of tomato in one cup of salad is OK.  A small amount of onion is OK.
  • String beans and snow peas are OK.
  • Cooked vegetables tend to raise blood sugar more rapidly than raw.
  • Use “Equal” aspartame tabs as a sweetener.  Don’t use “powdered” Splenda.
  • Avoid nuts: too easy to overeat.
  • For desert: sugar-free Jell-O Brand Gelatin.
  • Yogurt?  Plain, whole milk, unsweetened.  Flavor with cinnamon, Da Vinci syrups, baking flavor extracts, stevia or Equal.
  • Avoid balsamic vinegar.
  • Need fiber?  Bran crackers or soybean products.
  • “Ideally, your blood sugar should be the same after eating as it was before.”  85 mg/dl (4.72  mmol/l) is his usual goal.  If blood sugar rises by more than 10 mg/dl (0.56 mmol/l) after a meal, either the meal has to be changed or medication changed.
  • Protein is a source of glucose: keep protein amounts at meals constant from day to day, especially if taking glucose-lowering drugs.
  • The lowest-carb meal of the day should be breakafast.  Why?  Dawn phenomenon.
  • He promotes strenuous, prolonged exercise, especially weight training (extensive discussion and instruction in book).
  • Many diabetics on insulin need dose adjustments in 1/2 and 1/4 unit increments [news to me: if I ordered 4 and 1/4 units of insulin at the hospital, the nurses would laugh].
  • Typical rapid-acting insulin doses for his adult type 1 patients are 3-5 units.  The “industrial doses” of insulin seen or recommended by many physicians reflect diets too high in carbohydrate.
  • He says Lantus only acts for nine hours (nighttime injection) or 18 hours (AM injection).
  • He doesn’t like mixed insulins (e.g., 70/30).
  • Humalog and Novolog are more potent than regular insulin, so the dose is about 2/3 of the regular insulin dose
  • “Only a few of the 20 available [home glucose monitoring] machines are suitably accurate for our purposes.”  “None are suitably accurate or precise above 200 mg/dl [11.11 mmol/l].”
  • Vitamin C in doses over 250 mg interferes with fingertip glucose monitors.  Later he says doses over 500 mg cause falsely low readings.
  • He prefers regular insulin (45 minutes before meal) over Novolog and Humalog, because of its five-hour duration of action.
  • Insulin users need to check glucose levels hourly while driving.
  • His personal basal insulin is 3 units Lantus twice daily.
  • He urges use of glucose (e.g., Dextrotabs) to correct hypoglycemia.
  • He says hypoglycemia is rare on his regimen.
  • He has an entire chapter on gastroparesis.

Dr. Bernstein’s recommended eating program in a nutshell:  

  • Some similarities to the Atkins diet, which he never mentions.
  • No simple sugars or “fast-acting” carbs like bread and potatoes, because even type 2s have impaired or nonexistent phase 1 insulin response.
  • Limit carbs to an amount that will work with your injected insulin or your remaining phase 2 insulin response, if any.
  • “Stop eating when you no longer feel hungry, not when you’re stuffed.”
  • Follow a predetermined meal plan (each meal: same grams of carb and ounces of protein)
  • Six g (or less) of carbs at breakfast, 12 g (or less) at lunch and evening meal.  So his patients count carb grams and protein ounces.
  • Supplements are not required IF glucoses are controlled and eating a variety of veggies.  Otherwise you may need B-complex or multivitamin/multimineral supplement.
  • Recipes are provided.

His has four basic drug treatment plans, tailored to the individual.  They are outlined in the book.  Dr. B provides detailed notes on what he does with his personal patients.  

Overall impressions:  

  • Too complicated for most, and they won’t give up higher carb consumption.  It requires a high degree of committment and discipline.  In fact, I’ve never had a patient tell me they were on the Bernstein program.
  • If I had type 1 diabetes, I might well follow his plan or the Low-Carb Mediterranean Diet, NOT the high-carb diet recommended by the ADA and many dietitians.
  • And if I had type 2 diabetes?  Low-Carb Mediterranean Diet first, Diabetes Solution as second choice.
  • If one can get his hemoglobins A1c down to 5% with other methods, would that be just as good?  Dr. B would argue that all other methods have blood sugar swings that are too wide.
  • Many new ideas and techniques here, at least to me.
  • He pretty much reveals his entire program here, which is priceless.
  • I’m not sure this plan will work unless the patient’s treating physician is on-board.
  • His personal testimony and breadth of knowledge are very persuasive. 

Steve Parker, M.D.  

Disclosure:  I was given nothing of value by Dr. Bernstein or his publisher in return for this review.

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Filed under Book Reviews, Carbohydrate, Drugs for Diabetes, Protein

Has Low-Carb Eating Been Good for YOU?

Just add steamed broccoli and a spinach salad!

Just add steamed broccoli and a spinach salad!

Low-carb or carbohydrate-restricted eating has been very beneficial to many people with type 2 diabetes, judging by what I hear from my patients and read on the Internet.  By “beneficial,” I mean has this eating style helped you to control your glucose levels, lower your hemoglobin A1c, ameliorated complications, helped you lose weight,  energized you, or just plain made you feel better?

I would love to hear about your experiences with carb-restricted eating, both good and bad.  How much did you restrict your carb intake?  How did you go about it?  Did you go “full Atkins,” and restrict carbs to 20 or less grams a day?   Or were you more moderate, restricting carbs to 30% of total calories, as in The Zone Diet?  [The typical American diet derives 55-60% of all calories from carbohdrates.]  If you don’t care to share with the world, please send me an email to steveparkermd (at) gmail (dot) com.  I’ll keep all all personal responses to my email address private and confidential.

Thanks!

Steve Parker, M.D.

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My Ketogenic Mediterranean Diet and Low-Carb Eating: Six-Month Summary

I started my Ketogenic Mediterranean Diet on September 1, 2009.  After two months, I stopped compulsive record-keeping and food measurement and made a few other intentional tweaks: fish five times a week instead of seven miminum, more nuts (often two ounces a day—I like nuts and they’re convenient), less salad, more dark chocolate.  Otherwise the last four months have been similar to the initial two months of strict KMD.  My daily digestible carbohydrate intake has probably crept up to 40 g compared to 20-25 g on the strict KMD—this is still considered very low-carb. 

Accomplishments

Starting weight was 170 pounds (77.3 kg) on September 1.   After two months—8.6 weeks—my weight clearly stabilized at 155 lb (70.5 kg).  I lost the 15 lb (6.8 kg) over the first six weeks then just hovered around 155 lb.  So average weekly weight loss over the six weeks was 2.5 pounds.  Also lost a couple inches (5 cm) off my waist.

For the last four months—November through February—I’ve been eating the aforementioned liberalized KMD.  Weight has stayed around 155-157 lb (71 kg).  No calorie counting.  I eat as much as I want, except for carbs.  The experience of the first two months taught me how to eat 20-25 g of carbs in a day; it’s the gauge by which I estimate I’m eating 40 g daily now.

Has It Been Easy?

Yeah, relatively easy.  Two other adults in my house are also eating low-carb, which definitely helps.  Blogging here also helps me maintain compliance.  I promised myself to report everything—the good, the bad, and the ugly—honestly.  Accountability is important. 

Staying with the program may be easier for me than for others because I am heavily invested in it, psychologically and time-wise. 

It’s also been helpful for me to participate at two low-carb online communities: LowCarbFriends and Active Low-Carber Forums.  We support each other.  Thanks, guys.

I took diet holidays twice, for three days at both Thanksgiving and Christmas.  Gained three to five pounds (1.8 kg) each time on high-carb eating, but lost it over the next week by returning to the strict KMD.

Any Surprises?

Induction flu.  I’d never heard of it before.  Occurs typically on days 2–5 of very low-carb dieting: achiness and fatigue.  Others also experience headaches and dizziness, and it may last 1–2 weeks.

Rapid weight gain during my diet holidays (aka cheat days).  I was not gorging.  I figure the weight was mostly new glycogen in liver and muscle.  And water.

Eating fish more than once a day is a lot of fish!  Quickly boring, even unappetizing.  But that’s just me.  I need to be a more creative.  Most of my fish lately has been canned tuna.

Assuming that the Daily Values of various nutrients recommended by the U.S. Food and Drug Administration are valid, the KMD foods come up short in many vitamins and minerals.  I bet this is an issue (a problem?) with many, if not most, very low-carb diets if supplements aren’t used.  Those Daily Values are debatable, of course.  For instance, Gary Taubes argues that you don’t need much vitamin C if eating few carbs.  My nocturnal leg cramps and constipation were proof enough for me that I needed at least some supplements.  The recommended KMD supplements remedy the DailyValue shortfall in vitamins and minerals.  Dr. Richard K. Bernstein has a 30-gram carbohydrate diet for his diabetic patients and himself, as outlined in his Diabetes Solution book: no supplements are required.  

As time passes, I worry less about getting enough of various micronutrients.   I feel fine.  I’m still taking the recommended KMD supplements (5 pills a day) plus sugar-free Metamucil.   

I never had hunger that I couldn’t satisfy within the guidelines of the diet. 

No major trouble with cravings or longing for carbs.  I’ve gone six months now without whole grain bread, oatmeal, pizza, and pasta—very unusual for me.  I’d be OK never eating them again.  What I do miss are sweet, often fat-laced, carbohydrates: pie, cookies, cinnamon rolls, candy bars, cake, ice cream.  I doubt that desire will ever disappear, although it does for some who eat very low-carb.   

I counted calories only during the first two months of this experiment.  Remember, fats and proteins are unlimited.  Nevertheless, I ate fewer calories than my baseline intake.   This calorie reduction is a well-documented effect of very low-carb diets.  Fats and proteins are more satiating than carbohydrates.  It’s possible I’ve limited total calories subconsciously. 

[An interesting experiment would be to try to gain weight by over-eating fats and proteins while keeping total digestible carbs under 30 g/day.  Has it been done already?]

What’s Next?

I’d like to answer some intriguing questions.

Why did my weight loss stop where it did, at 155 lb (70.5 kg)? 

If I’d started the KMD at 270 lb (123 kg) instead of 170 lb (77.3 kg), would my weight loss have stopped at 255 lb (116 kg), 210 lb (95.5 kg) or 155 lb (70.5 kg)? 

Will two people, 300 lb each (136 kg), end up at the same final weight when following the program religiously?  Probably not, but why not?    

Six months ago, I believed many scientific studies supported the idea that a higher intake of carbohydrates is healthier, long-term, than the very low-carb Ketogenic Mediterranean Diet and other very low-carb diets.  Studies seemed to support higher carbohydrate intake in the form of traditional fruits, vegetables, legumes, and whole grains.  After reviewing the scientific literature over the last few months, I’m not so sure that higher carb consumption is necessary or beneficial for long-term health and longevity.  The evidence is weak.  Nearly all the pertinent studies are observational or epidemiologic—not the most rigorous science. 

On the other hand, I still can’t help feeling that the recommended eating styles of people like Monica Reinagel, Darya Pino, and Holly Hickman may be healthier than the KMD over the long run, at least for people free of diabetes and prediabetes.  What features unify those three?  Food that is minimally processed, fresh, locally produced when able, including a variety of fruits, vegetables, nuts, whole grains, and legumes. 

It seems that the human body is marvelously designed to survive, even thrive, with multiple ways of eating—but not all ways.   

The strongest evidence for higher carb consumption supports whole grains as a preventative for heart disease (coronary artery disease).  But the effect is modest. 

The argument against higher carb consumption is simple for people with diabetes and prediabetes: carbs raise blood sugar levels, sometimes to an unhealthy degree.  

I don’t see much role for highly processed, refined carbohydrates except as a cheap source of energy (calories).

What’s next for me is to formalize an opinion on which carbs, if any, and in what amount, to add back into the diet of those who have lost weight with the Ketogenic Mediterranean Diet.  The answer will probably be different for two groups:

  1. those who have diabetes, prediabetes, or metabolic syndrome
  2. healthy people who just need to control weight

The goal is to maximize health and longevity without tipping over into excessive carb intake that leads to overweight and obesity with associated illnesses.  

The traditional Mediterranean diet—long associated with health and longevity—is rich in carbohydrates.  The Ketogenic Mediterranean Diet—much lower in carbs—has great potential to help with loss of excess weight and control of blood sugar levels.  Does the KMD incorporate enough of the healthy components of the Mediterranean diet?  We may never know for sure.

Steve Parker, M.D.

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Filed under ketogenic diet, My KMD Experience

Low-Carb Killing Spree Continues

The choice is clear . . . NOT

Low-fat and low-carb diets produce equal weight loss and improvements in insulin resistance but the low-carb diet may be detrimental to vascular health, according to a new study in Diabetes.

Methodology

Researchers in the the UK studied 24 obese subjects—15 female and 9 male—randomized to eat either a low-fat (20% fat, 60% carbohydrate) or low-carb (20% carb, 60% fat) diet over 8 weeks.  Average age was 39; average body mass index was 33.6.  Most of them had prediabetes.  Food intake was calculated to result in a 500 calorie per day energy deficit (a reasonable reduced-calorie diet, in other words).  Study participants visited a nutritionist every other day, and all food was provided in exact weighed portions. 

Results

Both groups lost the same amount of weight, about 7.3% of initial body weight. 

Triglycerides dropped by a third in the low-carb group; unchanged in the low-fat cohort.  Changes in total cholesterol, LDL cholesterol, and HDL changes were about the same for both groups.

Systolic blood pressure dropped about 10 points in both groups; diastolic fell by 5 in both.

Aortic augmentation index” fell significantly in the low-fat group and tended to rise in the low-carb group.  According to the researchers, the index is used to estimate systemic arterial stiffness.  [In general, flexible arteries are better for you than stiff ones.  “Hardening-of-the-arteries,” etc.]  The low-fat group started with a AAI of 17, the low-carb group started at 12.  They both ended up in the 13-14 range. 

Peripheral insulin sensitivity improved significantly only in the low-carb group but “there was no significant difference between groups.”  No difference between the groups in hepatic (liver) insulin resistance. 

Fasting insulin levels fell about 20% in the low-fat group and about 40% in the low-carb group, a difference not reaching statistical significance (p=0.17).

The Authors’ Conclusions

This study demonstrates comparable effects on insulin resistance of low-fat and low-carbohydrate diets independent of macronutrient content.  The difference in augmentation index may imply a negative effect of low-carbohydrate diets on vascular risk.

My Comments

Yes, you can indeed lose weight over eight weeks on both low-fat and low-carb diets, if you follow them.  So diets DO work.  No surprise.

Loss of excess body fat by either method lowers your blood pressure.  No surprise.

Once again, concerns about low-carb/high-fat diets adversely affecting common blood lipids—increasing heart disease risk—are not supported.  No surprise

Hyperinsulinemia and insulin resistance are risk factors for development of diabetes and cardiovascular disease.  Results here tend to favor the low-carb diet.  I have to wonder if a study with just twice the number of test subjects would have shown a clear superiority for the low-carb diet.

The authors imply that aortic augmentation index is an important measure in terms of future cardiovascular health.  A major conclusion of this study is that a change in this index with the low-carb diet might adveresly affect heart health.  Yet they don’t bother to discuss this test much at all.  I’m no genius, but neither are the typical readers of Diabetes.  I doubt that they are any more familiar with that index than am I, and I’d never heard of it before. 

[Feel free to educate me regarding aortic augmentation index in the comment section.]

Unfortunately, many readers of this journal article and the associated news releases will come away with the impression, once again, that low-carb diets are bad for your heart. 

I’m not convinced.

Steve Parker, M.D.   

References:

Bradley, Una, et al.  Low-fat versus low-carbohydrate weight reduction diets.  Effects on weight loss, insulin resistance, and cardiovascular risk: A randomized control trialDiabetes, 58 (2009): 2,741-2,748.

Nainggolan, Lisa.  Low-carb diets hit the headlines again.  HeartWire, December 11, 2009.

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Filed under Carbohydrate, coronary heart disease, Fat in Diet, Prevention of T2 Diabetes, Weight Loss

Book Review: Good Calories, Bad Calories

Here’s my  review of good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease, by Gary Taubes, 2007.  I give it five stars on Amazon.com’s five-star system (“I love it”).

♦   ♦   ♦

This brilliant book deserves much wider currency among physicians, dietitians, nutritionists, and obesity researchers.  The epidemic of overweight and obesity over the last 30 years should make us question the reigning theories of obesity treatment and prevention.  Taubes questioned those theories and pursued answers wherever the evidence led.  He shares in GCBC his eye-opening, even radical, well-reasoned findings. 

Ultimately, this tome is an indictment of the reigning scientific community and public nutrition policy-makers of the last four decades.  That explains why, twoyears after publication, this serious, scholarly work has not been reviewed by the New England Journal of Medicine, the Journal of the American Medical Association, the American Journal of Clinical Nutrition , and the Journal of the American Dietetic Association (as of August, 2009).

In Part 1, Taubes examines the scientific evidence for what he calls the fat-cholesterol hypothesis.  More commonly known as the diet-heart hypothesis, it’s the idea that dietary fat (especially saturated fat) and cholesterol clog heart arteries, causing heart attacks.  Taubes finds the evidence unconvincing.  He’s probably right.

Part 2, The Carbohydrate Hypothesis, revives and older theory from the mid-twentieth cenury that is elsewhere called the Cleave-Yudkin carbohydrate theory of dental and chronic systemic disease.  In the carbohydrate theory,  high intake of sugary foods, starches, and refined carbhohyrates leads first to dental disease (cavities, gum inflammation, periodontal disease) then, later, to obesity and type 2 diabetes, coronary heart disease, perhaps even cancer and Alzheimer’s Disease.  These are, collectively, the “diseases of civilization.”

Part 3 tackles obesity and weight regulation.  Taubes writes that “…fattening and obesity are caused by an imbalance—a dysequilibirium—in the hormonal regulation of adipose [fat] tissue and fat metabolism.”  Think of the transformation of a skinny 10-year-old girl into a voluptuous young woman.  It’s not over-eating that leads to curvaceous fat deposits, growth of mammary tissue, and increase in height; it’s hormonal changes beyond her control. 

The primary hormonal regulator of fat storage is insulin, per Taubes.  Elevated insulin levels lead to storage of food energy as fat.  Carbohydrates stimulate insulin secretion and make us fat. 

Although it’s a brilliant book, by no means do I agree with all Taubes’ conclusions.  For instance, if carbohydrates cause heart disease, why is glycemic index only very weakly associated with coronary heart disease in men?  It’s way too early to blame cancer and Alzheimers on carbohydrates.  Primitive cultures may not exhibit many of the diseases of civilization because their members die too young.  Taubes is clearly an advocate of low-carb eating.  Why didn’t he directly address the evidence that fruits, vegetables, and whole grains in the right amounts are healthy?

I have to give Taubes credit for thinking “outside the box.”  His search for answers included reviews of esoteric literature and interviews with scientists in the fields of genetics, athropology, public policy, physiologic psychology, and paleontology, to name a few.

Towards the end of the book, Taubes describes a Mediterranean-style or “prudent” diet that is popular these days.  After five years of research for his book, he says that whether a very low-carb meat diet is healthier than a prudent diet “… is still anybody’s guess.”  It’s hard for me to put aside numerous observational studies associating health benefits with legumes, fruits, vegetables, and wholegrains.  So my “guess” is that the Mediterranean-style diet is healthier.  Perhaps the answer is different for each individual.  Heck, maybe the answer is low-carb Mediterranean.  Both Taubes and I are prepared to accept either result when we have proof-positive data.    

Taubes doesn’t base his opinions on late-breaking scientific results.  Instead, his research findings mostly span from 1930 to 1980, especially 1940-1960.  Once the fat-cholesterol (diet-heart) hypothesis took root around 1960 and blossomed in the 1970s, these data were ignored by the entrenched academics and policy-makers of the day. 

To be fair, I’ve got to mention this is not light reading.  A majority of people never read another book after they graduate high school.  Of those who do, many (like me) will have to look up the definition of “tautology,” “solecism,” etc. 

I was taught in medical school years ago that “a calorie is a calorie is a calorie.”  Meaning: if you want to lose excess weight, it doesn’t matter if you cut calories from fat, protein, or carbohydrates.  I really wonder about that now.

Steve Parker, M.D 

Additional Reading

Bray, George A.  Viewpoint: Good Calories, Bad Calories by Gary TaubesObesity Reviews, 9 (2008): 251-263.

Taubes, Gary.  Letter to Editor: Response to Dr. George Bray’s review of Good Calories, Bad CaloriesObesity Reviews, 10 (2008): 96-98.

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Filed under Book Reviews, Carbohydrate, Causes of Diabetes, coronary heart disease, Overweight and Obesity

Saturated Fat is Bad – If You’re a Mouse!

I was excited to see an article, “A Look at the Low-Carbohydrate Diet,” in the December 3, 2009, New England Journal of Medicine.  I was quickly disappointed.

Expecting a scholarly review of low-carb eating in humans, I found an exposition of a diet study in mice.  And not just your garden-variety mice.  These were a lab strain deficient in apolipoprotein E, which makes them particularly susceptible to atherosclerosis when fed a “Western” high-fat, moderate-protein, moderate-carbohydrate diet instead of standard lab chow.

Click on the HeartWire reference below for a discussion of the original mouse research.  I wrote a short post about it in August, 2009.

The article author, Dr. Steven R. Smith, states the usual concern that high-fat (especially saturated fat), high-protein, low-carb diets may cause cardiovascular disease such as atherosclerosis (hardening of the arteries).  He doesn’t mention the scientific evidence showing little or no role of total and saturated fat in cardiovascular disease.

I give credit to him for mentioning that high-fat low-carb diets area associated with improvement in several cardiovascular risk factors such as HDL cholesterol and blood pressure.  He thought they also improve ( lower) LDL cholesterol levels—not something I’ve been impressed with.  He didn’t mention the lowering of triglycerides so often seen. 

Dr. Smith explains that, compared with controls, mice eating the Western high-fat low-carb diet demonstrated progression of atherosclerosis, perhaps mediated by elevated nonesterified fatty acids and low numbers of endothelial progenitor cells.  These are not yet considered classic cardiovascular risk factors in humans.

To quote Dr. Smith, his main point is that . . .

The work of Foo et al suggests that the [high-fat low-carb] diet might increase the risk of cardiovascular disease through mechanisms that have nothing to do with these “usual suspects” [e.g., LDL and HDL cholesterol, blood pressure, C-reactive protein] and so provides a note of caution against reliance on the traditional cardiovascular risk factors as a gauge of safety.

He rightfully calls for investigation of these issues in humans, but . . .

In the meantime, the ageless advice applies to the consumer of the [high-fat low-carb] diet and other fad diets: caveat emptor.

Take Home Points

I agree that human studies are needed.

As the evidence in favor of the safety and efficacy of high-fat low-carb diets increases, the reigning medical establishment is looking for new ways to discredit them.  This attempt is pathetic.

Unfortunately, the typical physician reading NEJM will skim this article and conclude, “Yeah, I was right—the Atkins diet causes heart disease.  Low-fat high-carb is still the best.” 

If you have beloved pet mice that are deficient in apolipoprotein E, don’t feed them a high-fat low-carb diet.

Steve Parker, M.D.

References:

Smith, Steven R.  A Look at the Low-Carbohydrate Diet.  New England Journal of Medicine, 361 (2009): 2,286-2,288.  [This may cost you $10 USD.]

Foo, S.Y., et al.  Vascular effects of a low-carbohydrate high-protein dietProceedings of the National Academy of Sciences of the United States of America, 106 (2009): 15418-15423.   doi: 10.1073/pnas.0970995106  [This may cost you $10 USD.]

Busko, Marlene.  Atherosclerosis heightened in mice fed low-carb, high-protein diet.  HeartWire, August 26, 2009.  [Free]

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Filed under Carbohydrate, Fat in Diet