Tag Archives: Protein

Does Dietary Protein Affect Blood Sugars?

The protein in this can raise your blood sugar

I’m considering whether I should advise my patients with diabetes to pay careful attention to the protein content of their diet, assuming they’re not malnourished.  It’s an important issue to Dr. Richard K. Bernstein, who definitely says it has to be taken into account.

Protein can undoubtedly raise blood sugar levels.  But is the effect clinically significant?  Most  dietitians and physicians pay little attention to it as a source of hyperglycemia.  Here are some of Dr. Bernstein’s ideas pulled from the current edition of Diabetes Solution:

  • The liver (and the kidneys and intestines to a lesser extent) can convert protein to glucose, although it’s a slow and inefficient process.
  • Since the conversion process—called gluconeogenesis—is slow and inefficient, diabetics don’t see the high blood sugar spikes they would see from many ingested carbohydrates.
  • For example, 3 ounces (85 g) of hamburger patty could be converted to 6.5 g of glucose under the right circumstances.
  • Protein foods from animals (e.g., meat, fish, chicken, eggs) are about 20% protein by weight.
  • Dr. B recommends keeping protein portions in a particular meal consistent day-to-day (for example 6 ounces with each lunch).
  • He recommends at least 1–1.2 g of protein per kilogram of ideal body weight for non-athletic adults.  That’s more than the usual 0.8 g per kilogram.
  • The minimum protein he recommends for a 155-lb non-athletic adult is 11.7–14 ounces daily.
  • Growing children and athletes need more protein.
  • Each uncooked ounce of the foods on his “protein foods” list (page 181) provides about 6 g of protein.
  • On his eating plan, you choose the amount of protein in a meal that would satisfy you, which might be 3 ounces or 6–9 ounces.
  • If you have gastroparesis, however, you should limit your evening meal protein to 2 ounces of eggs, cheese, fish, or ground meat, while eating more protein at the two earlier meals in the day.

“In many respects—and going against the grain of a number of the medical establishment’s accepted notions about diabetics and protein—protein will become the most important part of our diet if you are going to control blood sugars just as it was for our hunter-getherer ancestors.”


I haven’t changed my thinking on this issue yet, but will let you know if and when I do.  I don’t talk much about protein in Conquer Diabetes and Prediabetes in part because I wanted to keep the program simpler than Dr. Bernstein’s.  Albert Einstein reportedly said, “Everything should be made as simple as possible, but not simpler.”

As with most aspects of diabetes, your mileage may vary.  The effect of dietary protein on blood sugars will depend on type 1 versus type 2 diabetes, and will vary from one person to another.  So it may be impossible to set rigid guidelines.

If interested, you can determine how much protein is in various foods at NutritionData.

Steve Parker, M.D.


Filed under Protein

High Protein Ketogenic Diet Beats High Protein/Medium Carb Diet in Men, at Least Short-Term

Low-Carb Steak

Low-Carb Steak

Scottish researchers last year reported greater weight loss and less hunger in obese men on a high-protein ketogenic diet compared to a high-protein, moderate-carbohydrate diet.


Dietary protein seems to be more satiating – able to satisfy hunger, that is – than carbohydrate and fat. 

The typical Western (especially American) diet derives about 55-60% of total calories from carbohydrates.  When carbohydrate intake is very low, under 20-30 grams per day for example, fat stores are utilized as a source of energy to replace carb calories, resulting in fat breakdown waste products called ketone bodies.  These are ketogenic diets.  In them, carbs are replaced usually by both extra fat and extra protein. 


Each of 17 obese men, 20 to 65 years old, were placed on two separate diets for four weeks each time.  Average weight was 111 kg.  Average body mass index was 35.  This was a residential program, but the subjects were allowed to leave and go to work.

  • Diet 1:  high-protein, low-carbohydrate, ketogenic.  30%, 4%, and 66% of energy (calories) as protein, carbohydrate, and fat, respectively.
  • Diet 2:  high-protein, medium-carbohydrate, nonketogenic.  30%, 35%, and 35% of calories as protein, carb, and fat, respectively.

Actually 20 men signed up, but three dropped out for personal reasons after starting. 

They could eat as much as they wanted. 


Subjects had no overall preference for either diet.  No differences in the diets for desire to eat, preoccupation with food, or fullness.  Weight loss was greater for the low-carb diet tahn with the medium-carb diet: 6.34 kg vs 4.35 (P < 0.001).  Subjects lost more weight on their first diet than on their second.  Fasting glucose and HOMA-IR (a test of insulin resistance) was lower than baseline for the low-carb diet but not the other.  Total and LDL cholesterol were tended to fall in response to both diets, but to a statistically significantly great degree only on the medium-carb diet.  When eating the low-carb diet, subjects ate 300 calories per day less than on the medium-carb diet.  [ketones were measures?]


We have to assume that study subjects were of Scottish descent.  Applicability of these results to other ethnic groups is not assured.  Similarly, results don’t necessarily apply to women.

I’m surprised the medium-carb dieters, eating all they wanted, lost weight at all.  Must be a result of the high protein content or lower-than usual carbohydrate content of the study diet.  Study authors cite others who found that doubling protein intake from 15 to 30% of calories reduces food intake, which should lead to weight loss. 

Since protein content was the same on both diets, the greater weight loss seen on the low-carb ketogenic diet was the result of lower caloric intake, in turn due to less hunger.  The reduced energy intake could be due to lower carb or higher fat intake, or both.  The researchers cite one study finding no satiating effect of fat.  Some say that ketone bodies reduce appetite. 

Although the medium-carb diet showed greater improvements in total and LDL cholesterol, the low-carb diet changes trended in the “right” direction (down).

On the low-carb ketogenic diet, lower glucose levels and insulin resistance would tend to help people with (or prone to) type 2 diabetes, prediabetes, and some cases of metabolic syndrome. 

Steve Parker, M.D.


Johnstone, Alexandra, et al.  Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum.  American Journal of Clinical Nutrition, 87 (2008): 44-55.

Weigle, D.S., et al.  A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations.  American Journal of Clinical Nutrition, 82 (2005): 41-48.

Comments Off on High Protein Ketogenic Diet Beats High Protein/Medium Carb Diet in Men, at Least Short-Term

Filed under Carbohydrate, ketogenic diet, Protein, Weight Loss

High- vs Low-Protein Weight-Loss Diet in Type 2 Diabetes


Mucho protein, amigo

Mucho protein, amigo

A high-protein weight-loss diet yielded greater reduction in LDL cholesterol in both sexes, and greater loss of abdominal fat in overweight type 2 diabetics, compared to a lower-protein diet.  Lower LDL cholesterol levels are associated with lower risk of heart attack.

This scientific study caught my eye because it utilized a high-monounsaturated fat diet for weight loss.  The Mediterranean diet is rich in monounsaturated fats, mostly from olive oil.

Researchers in Australia ran a study to determine the effect of high- versus lower-protein wieght loss diets on fat and lean tissue, glucose levels, and blood lipids.  For perspective, remember that a typical American diet has about 15% of calories from protein, 30% from fat, and 55% from carbohydrates.


This was their high-protein diet:  28% protein, 42% CHO, 28% fat (8% saturated fatty acids, 12% monounsaturated fatty acids, 5% polyunsaturated fatty acids).

The low-protein diet:  16% protein, 55% CHO, 26% fat (8% saturated fatty acids, 11% monounsaturated fatty acids, 5% polyunsaturated fatty acids).

They studied 54 obese men (19) and women (35) with type 2 diabetes during 8 weeks of energy restriction (1,600 kcal) and 4 weeks of energy balance.  Body composition was determined by dual-energy X-ray absorptiometry at weeks 0 and 12.


Average weight loss for both groups was 5 kg.  However, women on the HP diet lost significantly more total (5.3 vs 2.8 kg) and abdominal (1.3 vs 0.7 kg) fat compared with the women on the LP diet, whereas, in men, there was no difference in fat loss between diets (3.9 vs 5.1 kg).  Total lean mass decreased in all subjects independently of diet composition.  LDL cholesterol reduction was significantly greater on the HP diet (5.7%) than on the LP diet (2.7%).  Blood glucose levels were reduced 5 or 10% by both diet interventions.  Trigylcerides dropped 20% in both groups.  Insulin concentrations were reduced in both groups.  Subjects lose 2.1% lean mass overall, with no difference between the groups.

Conclusions of the Study Authors

Both dietary patterns resulted in improvements in the cardiovascular disease (CVD) risk profile as a consequence of weight loss. However, the greater reductions in total and abdominal fat mass in women and greater LDL cholesterol reduction observed in both sexes on the HP diet suggest that it is a valid diet choice for reducing CVD risk in type 2 diabetes.

Take-Home Points

This was a relatively small study, so results may not be widely applicable.

Substituting proteins for carbs doesn’t seem to be detrimental to people with type 2 diabetes needing to lose weight, and may be advantageous:  greater total and abdominal fat loss in women, greater reductions in LDL cholesterol for both sexes.   At least in the short run.

Nephrologists will be concerned that the higher-protein diet, if sustained long-term, could lead to kidney damage.

Current dogma is that the lower-carb (high-protein) dieters should have had lower blood glucose, triglycerides, and HgbA1c levels:  not seen here.

Calorie-restricted diets tend to lower glucose levels and improve lipids, despite diet composition.

Reference:  Parker, Barbara et al.  Effect of a High-Protein, High–Monounsaturated Fat Weight Loss Diet on Glycemic Control and Lipid Levels in Type 2 Diabetes.  Diabetes Care,  25 (2002): 425-430.    From CSIRO Health Sciences and Nutrition, Adelaide, Australia.

1 Comment

Filed under Carbohydrate, Protein, Weight Loss