Tag Archives: William Yancy

Low-Carb Diets Killing People?

Animal-based low-carb diets are linked to higher death rates, according to a recent study in the Annals of Internal Medicine.  On the other hand, a vegetable-based low-carb diet was associated with a lower mortality rate, especially from cardiovascular disease.

As always, “association is not causation.”

It’s just a matter of time before someone asks me, “Haven’t you heard that low-carb diets cause premature death?”  So I figured I’d better take a close look at the new research by Fung and associates.

It’s pretty weak and unconvincing.  I have little to add to the cautious editorial by William Yancy, Matthew Maciejewski, and Kevin Schulman published in the same issue of Annals.

The study at hand was observational over many years, using data from the massive Nurses’ Health Study and Health Professionals’ Follow-up Study.  To find the putative differences in mortality, the researchers had to compare the participants eating the most extreme diets.  The 80% of study participants eating in between the extremes  were neutral in terms of death rates.

They report that “…the overall low-carbohydrate diet score was only weakly associated with all-cause mortality.”  Furthermore,

These results suggest that the health effects of a low-carbohydrate diet may depend on the type of protein and fat, and a diet that includes mostly vegetable sources of protein and fat is preferable to a diet with mostly animal sources of protein and fat.

In case you’re wondering, all these low-carb diets derived between 35 and 42% of energy (total calories) from carbohydrate, with an average of 37%.  Anecdotally, many committed low-carbers chronically derive 20% of calories form carbohydrate (100 g of carb out of 2,000 calories/day).  The average American eats 250 g of carb daily, 50-60% of total calories.

Yancy et al point out that “Fung and coworkers did not show a clear dose-response relationship in that there was not a clear progression of risk moving up or down the diet deciles.”  If animal proteins and fats are lethal, you’d expect to see some dose-response relationship, with more deaths as animal consumption gradually increases over the deciles.

ResearchBlogging.orgThe Fung study is suggestive but certainly not definitive.  Anyone predisposed to dietarycaution who wants to eat lower-carb might benefit from eating fewer animal sources of protein and fat, and more vegetable sources.  Fung leaves it entirely up to you to figure out how to do that. Compared to an animal-based low-carb diet, the healthier low-carb diet must subsitute more low-carb vegetables and higher-fat plants like nuts, seeds, seed oils and olive oil, and avocadoes, for example.  What are higher-protein plants?  Legumes?

You can see how much protein and fat are in your favorite vegetables at the USDA Nutrient Database.

The gist of Fung’s study dovetails with the health benefits linked to low-meat diets such as traditional Mediterranean and DASH.  On the other hand, if an animal-based low-carb diet helps keep a bad excess weight problem under control, it too may by healthier than the standard American diet.

See the Yancy editorial for a much more detailed and cogent analysis.  As is so often the case, “additional studies are needed.”

Steve Parker, M.D.

Reference: Fung TT, van Dam RM, Hankinson SE, Stampfer M, Willett WC, & Hu FB (2010). Low-carbohydrate diets and all-cause and cause-specific mortality: two cohort studies. Annals of internal medicine, 153 (5), 289-98 PMID: 20820038

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Filed under Carbohydrate, coronary heart disease, Vegetables

Low-Carb Ketogenic Diet for Overweight Diabetic Men: A Pilot Study

A low-carb ketogenic diet in patients with type 2 diabetes was so effective that diabetes medications were reduced or discontinued in most patients, according to U.S. researchers.  The 2005 report recommends that similar dieters be under close medical supervision or capable of adjusting their own medication, because the diet lowers blood sugar  dramatically. 


Twenty-eight overweight people with type 2 diabetes were placed on the study diet and followed for 16 weeks.  Seven people dropped out, so the analysis involved 21, of which 20 were men—the study was done at a Veterans Administration clinic.  Thirteen were caucasian, eight were black.  Average age was 56; average body mass index was 42.  The seven dropouts were unable to come to the scheduled meetings or couldn’t follow the diet.  No dropout complained of adverse effects of the diet.


Participants were instructed on the Atkins Induction Phase diet, which daily includes:

  • under 20 g carbohydrate
  • one cup of low-carb vegetables
  • two cups of salad greens
  • four ounces of hard cheese
  • unlimited meat, poultry, fish, eggs, shellfish
  • a multivitamin

At the outset, diabetes medication dosages were reduced in this general fashion: insulin was halved, sulfonyureas were halved or discontinued.  If the participant were taking a diuretic (fluid pill), low doses were discontinued; high doses were halved.

Study subjects returned every two weeks for diet counseling and medication adjustment (based on twice daily glucose readings and episodes of hypoglycemia).  Food cravings and/or good progress on weight goals triggered a 5-gram (per day) weekly increase in carbohydrate allowance.  In other words, if a participant’s weight loss goal was 20 pounds and he’d already lost 10, he could increase his daily carbs during the next week from 20 to 25 g.  Carbs could be increased weekly by five gram increments as long as weight loss progressed.  [This is typical Atkins.]   Food records were analyzed periodically.   


  • hemoglobin A1c decreased from an average baseline of 7.5% down to 6.3% (a 1.2% absolute decrease and 16% relative drop)
  • the absolute hemoglobin A1c decrease was at least 1.0% in half of the participants
  • diabetic drugs were reduced in 10 patients, discontinued in seven, and unchanged in four
  • average body weight decreased by 6.6%, from 131 kg (288 lb) to 122 kg (268 lb)
  • triglycerides decreased 42%, while cholesterols (total, HDL, and LDL) didn’t change significantly
  • no change in blood pressures
  • average fasting glucose decreased by 17% (by week 16)
  • uric acid decreased by 10%
  • no serious adverse effects occurred
  • one hypoglycemic event involved EMS but was treated without transport
  • only 27 of 151 urine ketone measurements  were greater than trace

My Comments

The degree of improvement in hemoglobin A1c—our primary gauge of diabetes control—is equivalent to that seen with many diabetic medications.  I see many overweight diabetics on two or three drugs and a standard “diabetic diet,” and they’re still poorly controlled.  This diet could replace the expense and potential adverse effects of an additional drug.   

In August this year I blogged about a study comparing the Atkins diet with a traditional low-fat diet in overweight diabetic black women in the U.S.  As measured at three months, the Atkins diet proved superior for weight loss and glucose control.

This study at hand is small, but certainly points to the effectiveness of an Atkins-style very low-carb ketogenic diet in overweight men with type 2 diabetes.

Steve Parker, M.D.

Yancy, William, et al.  A low-carbohydrate, ketogenic diet to treat type 2 diabetes [in men].  Nutrition and Metabolism, 2:34 (2005).   doi: 10.1186/1743-7075-2-34


Filed under Carbohydrate, ketogenic diet, Overweight and Obesity, Weight Loss