Tag Archives: Atkins diet

Low-Carb Ketogenic Diet Beats Low-Glycemic Index Diet in Overweight Type 2 Diabetes

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Avoid the needle with a low-carb ketogenic diet

Duke University (U.S.) researchers demonstrated better improvement and reversal of type 2 diabetes with an Atkins-style diet, compared to a low-glycemic index reduced-calorie diet.

Methodology

Ninety-seven overweight and obese adults, 78% women and 40% black, were randomly assigned to either:

  • a very low-carb ketogenic diet (Atkins induction phase, as in Atkins Diabetes Revolution) or
  • a low glycemic-index index calorie-restricted diet (The GI Diet by Rick Gallop). 

Thirty-eight were in the Atkins group; 46 in the low-glycemic index (low-GI) group.  Seventeen dropped out of each group before the end of the 24-week study.  Average weight was 234.3 pounds (106.5 kg); average body mass index was 37.  The Atkins group averaged 13% of total calories from carbohydrate; the low-GI cohort averaged 44%. 

Results

Both groups lost weight and had improvements in hemoglobin A1c, fasting insulin, and fasting glucose. 

The Atkins group lowered their hemoglobin A1c by 1.5% (absolute drop, not relative) versus 0.5% in the other group. 

The Atkins group lost 11.1 kg versus 6.9 kg in the other group. 

The Atkins group increased HDL cholesterol by5.6 mg/dl versus no change in the other group. 

All the aforementioned comparisons were statistically significant. 

Diabetes medications were stopped or reduced in 95% of the Atkins group versus 62% of the low-GI group.

Total and LDL cholesterol levels were unchanged in both groups. 

Triglycerides fell significantly only in the Atkins group.

My Comments

You may be interested to know that this study was funded by the Robert C. Atkins Foundation.

One strength of this study is that it lasted for 24 months.  Many similar studies last only eight to 12 weeks.  A drawback is that, with all the drop-outs,  the number of participants is low. 

The GI Diet performed pretty well, too, all things considered.  Sixty-two percent reduction or elimination of diabetes drugs—not bad.  For a six-year-old book, it’s still selling fairly well at Amazon.com.  That may be why they chose it as the comparison diet.

The diet with fewer carbohydrates—Atkins induction—was most effective for  improving control of blood sugars.  So effective, in fact, that the researchers sound a note of warning:

For example, participants taking from 40 to 90 units of insulin before the study were able to eliminate their insulin use, while also improving glycemic control.  Because this effect occurs immediately upon implementing the dietary changes, individuals with type 2 diabetes who are unable to adjust their own medication or self-monitor their blood glucose should not make these dietary changes unless under close medical supervision.  

[Not all insulin users were able to stop it.]

Overall, lipids were improved or unchanged in the Atkins group, despite the lack of limits on saturated fat intake.  A common criticism of the Atkins diet is that it has too much saturated fat, leading to higher total and LDL cholesterol levels, which might raise long-term cardiovascular risks.  Not so, here. 

When you reduce carbohydrate intake, the percentages of fat and protein in the diet also change.  In this Atkins diet, protein provided 28% of daily calories, and fat 59%.  In the low-GI diet, protein provided 20% of daily calories, fat 36%.  The beneficial effects of the Atkins diet probably reflect the low carbohydrate consumption rather than high protein and fat. 

The Atkins induction-phase diet was clearly superior to the low-glycemic index diet in this overweight diabetic sample, without restricting calories.

Steve Parker, M.D.

Reference:  Westman, Eric, et al.  The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitusNutrition & Metabolism 2008, 5:36   doi:10.1186/1743-7075-5-36

Additional Reading

Samaha, F., et al.  A low-carbohydrate as compared with a low-fat diet in severe obesity.  New England Journal of Medicine, 348 (2003): 2,074-2,081.

Boden, G., et al.  Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes.  Annals of Internal Medicine, 142 (2005): 403-411.

Vernon, M., et al.  Clinical experience of a  carbohydrate-restricted diet: Effect on diabetes mellitus.  Metabolic Syndrome and Related Disorders, 1 (2003): 233-238.

Yancy, W., et al.  A pilot trial of a low-carbohydrate ketogenic diet in patients with type 2 diabetes.  Metabolic Syndrome and Related Disorders, 1 (2003): 239-244.

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Filed under Carbohydrate, Glycemic Index and Load, ketogenic diet, Overweight and Obesity

My Ketogenic Mediterranean Diet: Day 29 and Week 4 Update

monument valley navajo tribal parkWeight: 160.5 lb (72.95 kg)

Waist circumference: 35¼ inches (89.5 cm)

Transgressions: not eating as much fish as I should, and ate 2-3 fl oz of barbecue sauce having unknown carb content

Exercise: none

Comments

Down 1.5 lb (0.68 kg) for the week.  Starting weight September 1 was 170 lb (77.3 kg).  Down a total of 9.5 lb (4.32 kg) over four weeks. 

Another 3-day out-of-town trip interfered with calorie counting and nutrient analysis since I was away from my computer.  But remember, the Ketogenic Mediterranean Diet doesn’t require calorie counting.  I’m just doing it for scientific purposes.  I fully expect at some point I will stop losing weight, and I want to know my daily caloric intake at that point.  Will it rise to the 2,200-2,400 range, which I believe to be my baseline?

I saw an interesting documentary on the Atkins diet posted by Dr. Dan at Darwin’s Table.  Dr. Dan is a paleo diet advocate.  From the documentary, apparently produced in the UK, I learned that feeling “peckish” means you are “somewhat hungry” (also means irritable) and a “stone” equals 14 pounds (6.4 kg).  The sound track reminds me of the Austin Powers movies. 

If you like barbecue and are ever in Wikiup, Arizona, USA, don’t miss “Eat at Joe’s Barbecue.”  It’s Texas-style BBQ.  Best barbecue brisket and ribs I’ve ever had outside of Texas.

I watched my wife and daughter eat ice cream at Baskin-Robbins, and had, surprisingly, no temptation.  I love BDR ice cream.  I ate 20 grams of Lindt dark chocolate with them instead.  I saw some sugar-free ice cream, so I asked the clerk, “Do you have nutritional analysis info on that?”  She replied, “Sir, this is an ice cream store…” 

This is a typical days’ food:

  • Breakfast: eggs and meat (beef, sausage, bacon, or ham).  I fry eggs in olive oil or butter.  Occassionally sauté tomatoes or onions in olive oil.
  • Lunch and Dinner: Salad dressed with extra virgin olive oil vinaigrette, with added fish (usually canned) or chicken.
  • Glass of red wine with dinner.
  • Snack: Nuts, cheese, or both.

Daily average nutrient analysis for four days:

  • Macronutrients as percentage of total energy: 7% carbohydrate, fat 59%, protein 26%, alchohol 8%
  • Digestible carbohydrate: 25 g
  • Fiber: 9 g
  • Calories: 1650
  • Looking at % Daily Values for a 2,000 calorie diet, this diet may be deficient in vitamins and minerals: C, D, E, thiamine, B6, folate, pantothenic acid, iron, manganese, magnesium, potassium, sodium, copper, and calcium.  [However, I am taking two Centrum multivitamin/multimineral supplements plus extra vitamin D 400 IU, which would correct nearly all of these, as discussed at my Week 2 Recap.] 

I am starting to miss my sweet carbohydrates, like Reese’s Peanut Butter cups, apple pie, and ice cream.  My birthday is coming up.  What . . . No cake?  It’s time to think about a “cheat day,” perhaps once a month.  The Advanced Mediterranean Diet has one every two weeks.

-Steve

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My Ketogenic Mediterranean Diet: Day 23

CB104470Weight: 161 lb

Transgressions: none

Exercise: 60 minutes shovelling horse poo and picking up rocks from a new corral

Comments

I followed Dr. Atkins New Diet Revolution for 10 weeks in 2003.  When my daughter was 3-years-old, I realized that my exercise habit—six hours a week either at a gym or running—had been interfering with my family time and helping out around the house.  So I quit exercising for 3–4 years and, therefore, gained some weight.  In 2003, my Atkins starting weight was 178 lb, waist 37 inches.  Goal weight was 162-165.  I lost 11 pounds on Atkins.  Towards the end I was bored and increasingly noncompliant.  Here are my 2003 verbatim notes summarizing my experience with Atkins:

Lost 10 lbs [4.55 kg] over first 5 weeks, ½ of that in the first 2 weeks.  I have not exercised nearly as much as he recommended.  Have not suffered much hunger or sense of deprivation.  No wt change in last 6 weeks, coinciding with poor exercise compliance (may or may not be related).  Note that I really don’t have much wt to lose at this point, just a cosmetic amount.  At some point, even if fully compliant with Atkins, wouldn’t wt loss stop in everyone?  I have no idea how may calories I am eating now.  With wt stable, will assume it is around 2000-2400 cal/day.  Ten years ago when I was exercising religiously, my wt-maintaining intake was 2400 cal.  Probably closer to 2000 now in view of aging and sedentariness.  Over the last 6 weeks of stable wt, however, I was mostly compliant with his induction-phase food prescription.  To lose wt now I probably need to exercise more and count actual calories.  Even took his recommended Essential Oils supplement (2/day) and Basic 3 vitamin supplement (2 instead of 3/day).  He has convinced me I am a carbaholic.  Sugars and refined carbs are empty calories that don’t provide much except energy, which in excessive amounts is stored as fat.  But I cannot yet abandon the dogma that saturated fats (e.g., red meat) can be harmful to circulation over the long run.  And his carb restriction would keep me from eating adequate beneficial vegetables.  If I want to eat sweets and refined carbs, I will have to exercise more and/or give up fats, vegetables, or proteins.  Atkins makes a lot of sense for obese people who love carbs and overeat them.  I also like the rapid results of induction phase.  I admire the simplicity of the induction phase.  Thereafter, the “Ongoing Weight Loss” and “Lifetime Maintenance” phases do require counting carbs.  The latter phase, for me, would allow 40-60 gm/day, unless I were a vigorous exerciser (then 90+ gm).  A serving of apple pie has 58 gm.

Now it’s six years later and I’m much more willing to reconsider that dogma that saturated fats cause impaired circulation (atherosclerosis).  But I still think that fruits, vegetables, whole grains, and legumes are healthy for many people.

-Steve

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Atkins Diet Beats Low-Fat Diet Over Three Months in Overweight Diabetic Black Women

MPj04384250000[1]A recent study compared effects of a low-carb versus low-fat diet in overweight diabetics (mostly blacks).  After one year, the only major difference they found was  lower HDL cholesterol in the low-carb eaters.  The low-carb diet was more effective measured at three months into the study.  Study participants were overwhelmingly black women, so the findings may not apply to you.

Background

The authors note at the outset that:

Optimal weight loss strategies in patients with type 2 diabetes continue to be debated, and the best dietary strategy to achieve both weight loss and glycemic control . . . is unclear.

They also note that in short-term randomized studies, low-carb diets help improve glucose control in type 2 diabetics.

Methodology

Participants (105) were randomized to either:

  • a low-fat diet in the fashion of the Diabetes Prevention Program, with a fat gram goal of 25% of energy needs, or . . .
  • the Atkins diet, including the 2-week induction phase and gradually increasing carb grams weekly, etc.

The adult partipants were black (64%), Hispanic (16%), white (15%), or other.  Women were 80% of the group.  Average age 54.  Average weight 215 pounds (98 kg).  Average BMI 36.  Most of them were taking metformin, half were taking a sulfonylurea, 30% were on insulin.  Thiazolidinedione drugs were discontinued since they cause weight gain as a side effect.  Short-acting insulins were changed to glargine (Lantus) to help avoid hypoglycemia.  For the low-carb group initially, insulin dosages  were reduce by half and sulfonylureas were stopped (again, to minimize hypoglycemia).  For the low-fat group, insulin was reduced by 25% and sulfonylurea by 50%.  Metformin was not adjusted.  Subjects were instructed to keep daily food diaries.  Goal rate of weight loss was one pound per week.   

Results

The drop-out rate by the end of 12 months was the same in both groups – 20%.  The low-carbers lost weight faster (3.7 lb/month) in the first three months, but by month twelve each group had the same 3.4% reduction of weight (6.8 lb or 3 kg).  As measured at 3 months, low-carbers were down 11.4 lb (5.2 kg) and low-fat dieters were down 7 lb (3.2 kg).  Maximum weight loss was at 3 months, then they started gaining it back.  At 12 months, low-carb subjects using insulin were on 10 less units, while low-fat dieters were using 4 more units (not statistically significant).  Hemoglobin A1c measured at 3 months was down 0.64 in the low-carb group and down0.26 in the low-fat.  By 12 months, HgbA1c’s were back up to baseline levels for both groups.  Blood lipids were the same for both groups at 12 months except HDL was about 12% higher in the low-carb dieters.

At baseline, subjects derived 43% of calories from carbohydrates, 36% from fats, 23% from proteins.  At three months, the low-carb group ate 24% of calories as carbohydrates (estimated at 77 grams of carb daily) and 49% from fat.  The low-fat group at 3 months derived 53% of calories from carbohydrate (199 grams/day) and 25% from fat. Diet compliance deteriorated as time passed thereafter. 

Study Author Conclusions

After one year, the low-carb and low-fat groups had similar weight reductions.  The low-carb dieters raised their HDL cholesterol levels significantly [which may protect against heart disease].

My Comments

Lasting weight loss is difficult!  Down only 6.8 pounds for a year of  effort. 

These study participants needed to lose a lot more than 6.8 pounds.  They needed to lose 50.  Both groups were woefully noncompliant with diet recommendations by the end of the study year.  They were eating more carbs or other calories than they were assigned.  But their results weren’t much different than other groups studied for an entire year. 

How do we keep people fired up about maintaining their weight-loss efforts?  The solution to that problem will win someone a Nobel Prize.

The Atkins diet was superior – for weight loss and glycemic control – when measured at three months, when compliance by both groups was still probably fairly good.

Results of this study may apply only to black women.  There weren’t enough men and other ethnic groups to make meaningful comparisons.    

Steve Parker, M.D.        

Reference:  Davis, Nichola, et al.  Comparative study of the effects of a 1-year dietary intervention of a low-carbohydrate diet versus a low-fat diet on weight and glycemic control in type 2 diabetes.  Diabetes Care, 32 (2009): 1,147-1,152.

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ADA Now Says Low-Carb Diets OK for Overweight Type 2 Diabetics

CB037166Eighty-five percent of type 2 diabetics are overweight or obese.  Overweight either causes or aggravates many cases of diabetes.

For the last quarter-century, many U.S. government agencies and healthcare organizations have advocated a low-fat diet for overweight people, including type 2 diabetics.  Recent studies have documented that low-carbohydrate diets can also be effective in weight loss.  Low-carb diets replace carbohydrates with either fats or proteins, or both.  The A to Z Weight Loss Study compared the Atkins, Ornish, LEARN, and Zone diets in 311 overweight pre-menopausal women.  The Atkins group tended to lose a bit more weight. Changes in lipid profiles, waist-hip ratios, fasting insulin and glucose levels, blood pressure, and percentage of body fat were comparable or better with Atkins versus the other diets.

The Amerian Diabetes Association now gives the go-ahead for use of low-carb diets as a weight-control method for type 2 diabetics.  Previously, the organization had recommended against diets that restrict carbohydrates to less than 130 grams daily.  (A baked potatoe without the skin has 30 grams.)  Understand that the ADA does not endorse low-carb diets for weight loss or diabetes management.  They simply say that either low-carb or low-fat calorie-restricted diets might be effective for up to one year.

I caution you that low-carb diets may be deficient in fiber, minerals, vitamins, and phytonutrients that may be very beneficial in terms of long-term health and longevity.

The tide has been turning against low-fat diets for the last six years.

Steve Parker, M.D.

Reference: American Diabetes Association.  Clinical Practice Recommendations 2008.  Diabetes Care, 31 (2008): S61-S78.

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Are High-Protein Weight-Loss Diets Safe and Effective?

Animal protein

Animal protein

According to researchers at Tufts University, high-protein weight-loss diets may be effective and safe except for people prone to kidney stones, chronic kidney disease, and people with diabetes.  Long-term effects on bone health – osteoporosis, specifically – might be a problem.

High-protein weight-loss diets have been popular for a while.  “Protein Power” by Drs. Michael and Mary Eades is an example.  The Atkins diet may be, too.  If you increase the protein in your diet, you generally are decreasing carbohydrates or fat, or both, at the same time.   

I found a scientific review article from way back in 2002 and thought I’d share some of the highlights.  The authors seem very thorough; the article has 150 citations of other research articles. 

Note that the RDA – recommended dietary allowance – for protein is 0.8 gm/kg.  The typical U.S. resident eats about 1.2 gm/kg of protein daily, which is about 15% of total energy (calorie) intake.   Public health agencies recommend that we get 15% of our energy from protein, 30% from fat, and 55% from carbohydrate.  The authors of the study at hand propose that a high-protein diet be defined as:

  • protein intake of at least 25% of energy in weight-stable individuals, or
  • at least 1.6 gm/kg (of ideal body weight)  in people actively losing weight

Here are some of the authors’ points I found interesting:

  1. Higher-protein meals do seem to suppress hunger and enhance satiety, so high-protein dieters probably eat less (average 9% less calories).  It’s unknown if the effect lasts longer than six months.  Most of the evidences is much shorter-term.
  2. High-protein intake increases the thermic effect of feeding, meaning energy expenditure increases simply as a result of eating protein.  In other words, it takes energy to process the food we eat.  Compared with fats and carbohydrates, protein contributes twice as much to the thermic effect of feeding.  Most of the thermic effect of protein results from protein synthesis, i.e., the production of new proteins, which requires energy.  This has a minimal influence on body weight. 
  3. The authors write that “these studies do not support a role for high dietary protein in preventing loss of lean tissue during negative energy balance [actively cutting calories to lose weight], provided that dietary protein intake at least meets the RDA.”   
  4. They found only one study comparing a high-protein diet (25% of calories) with a low-fat, high-carbohydrate diet (12% protein).  Both diets were 30% fat.  Both groups could eat all they wanted.  Weight and fat loss were greater in the high-protein group, about twice as much. 
  5. High-protein diets over the long run may cause low-grade metabolic acidosis, leading to net loss of body calcium through the urine, with associated weak bones and kidney stones.   Animal proteins in particular do this.  Bone loss may be alleviated by calcium supplementation.  Fruits and vegetables may counteract the acidosis effect.  Nearly all of these statements are based on short-term studies.
  6. People with chronic kidney disease (ask your doctor) have slower disease progression and live longer if they limit protein to the RDA level. 
  7. Animal protein intake is directly related to risk of symptomatic kidney stones.
  8. Protein produces a blood glucose response, although not as much as with carbohydrate.  Insulin response is also seen.  In type 2 diabetics, the insulin response to 50 grams of animal protein was the same as to 50 grams of glucose.  A few studies suggest that in type 2 diabetics a high-protein diet may be detrimental to glucose control and/or insulin sensitivity.  Also note that people with diabetes are prone to chronic kidney disease, which could be worsened with a high-protein diet.  

Take-Home Points

See first paragraph.  The article authors may have different opinions now, based research published over the last seven years. 

Steve Parker, M.D.

Reference:  Eisenstein, Julie, et al.  High-protein weight-loss diets:  Are they safe and do they work?  A revew of the experimental and epidemiologic data.  Nutrition Reviews, 60 (2002): 189-200.

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Comparison of Mediterranean, Low-Carb, and Low-Fat Weight-Loss Diets

The July 17, 2008, issue of the New England Journal of Medicine has a well-done study comparing the Mediterranean, low-carb, and low-fat weight-loss diets in an Israeli population over the course of two years.  The researchers conclude that “Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets.  The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.”

How was the study set up?

Moderately obese participants (322) were randomly assigned to one of the three diets: 1) low-fat, calorie-restricted, 2) Mediterranean, calorie-restricted, or 3) low-carbohydrate, non-restricted.  Calories in the low-fat and Mediterranean diets were “restricted” to 1800 per day for the men, 1500 for the women.  Average age of participants was 52, and average body mass index was 31.  [A 5-foot, 10-inch man weighing 216 pounds (98.2 kg) has a BMI of 31.]  Nearly all participants – 277 or 86% of the total – were men.  So there were only 45 women.  Forty-six participants had type 2 diabetes.

The low-fat diet was based on the American Heart Association guidelines of 2000: 30% of calories from fat [this isn’t very low], 10% of calories from saturated fat, cholesterol limited to 300 mg/day.  [The AHA revised their guidelines in 2006.]  Low-fat dieters ”were counseled to consume low-fat grains, vegetables, fruits, and legumes and to limit their consumption of additional fats, sweets, and high-fat snacks.”

The Mediterranean diet was based on the recommendations of Walter Willett and P.J. Skerrett as in their book, Eat, Drink, and be Healthy: The Harvard Medical School Guide to Health Eating.  Mediterranean dieters ate 2 fish meals per week, a handful of nuts daily, 30-45 grams of extra virgin olive oil per day, etc.  [One tablespoon of olive oil is 14 grams.]  The AHA states that “this diet reflects the current recommendations from the American Heart Association.”  There were no specific recommendations regarding alcohol in any of the diets.

The low-carb diet was based on  Atkins’ New Diet Revolution of 2002.  The goal was to provide 20 grams of carbohydrate per day for the 2-month induction phase, with a gradual increase to a maximum of 120 grams daily to maintain weight loss.  Total calories, protein, and fat were not limited.  “Participants were counseled to choose vegetarian sources of fat and protein….”

Whole grains were recommended for the low-fat and Mediterranean cohorts.

All participants worked at the same nuclear research facility in Dimona, Israel.  They were given careful instructions, initially and periodically, regarding the diet to which they were assigned.  Lunch is the main meal of the day in Israel, and they all ate lunch at the facility’s self-service cafeteria, which prompted them to choose the proper food items.  I assume they were told to maintain the diet when off-duty.  Adherence to the diets was assessed by a food-frequency questionnaire.

Findings

  • After 24 months, how many participants were still involved?  90% in the low-fat group, 85% in the Mediterranean, 78% in the low-carb.
  • There was little change in the usage of medications, and no significant differences among the groups.
  • Daily energy intake (calories or kcal) decreased from baseline levels significantly – about 450 calories – in all groups at 6, 12, and 24 months compared with baseline, with no significant differences among the groups in the amount of decrease.
  • All groups started with 51% of energy intake (calories) from carbohydrate.
  • At 24 months, the low-carb dieters were getting 40% of their daily calories as carbohydrates.  The other two groups were eating 50% of energy intake from carbs. [This still seems like a lot of carbs on the Atkins diet.  A gram of carbs has 4 calories.  The stated carbohydrate goal was a maximum of 120 grams of carbs daily, on a diet of 1800 calories.  So 120 grams of carbohydrate should be 27% of total daily calories.  At no point did the low-carb group reduce their average percentage of calories from carbohydrates under 40%.  OK, maybe be in the first two weeks but those data are not reported.  On an 1800 calorie diet, 40% of calories from carbs would be 180 grams.]
  • At 24 months, the low-carb dieters were getting 39% of their daily calories as fat.  The other two groups were in the 30-33% range.
  • Baseline fat intake for all groups was 31-32% of total calories, with saturated fat being 10% of the fat calories.
  • The low-fat cohort dropped their fat calories from 31 to 30% of total calories, which is essentially no change from baseline percentage.
  • At 24 months, the low-carbers were getting 22% of their daily calories from protein.  The other groups were at 19%.  [The low-carb Atkins diet is often criticized as having too much protein.]
  • Only the low-carb group made major changes in macronutrient composition of their diet.  Macronutrients are protein, fat, and carbohydrates.  This Atkins group increased saturated fat from 10 to 12% of total calories, reduced carbs from 51 to 40% of calories, increased protein from 19 to 22% of calories, and increased total fat from 32% to 39% or total calories.
  • All cohorts lost weight, but losses were greater in the low-carb and Mediterranean groups.  For the 272 participants who completed the full 24 months of intervention, the losses averaged 3.3 kg (7.3 lb) for the low-fat group, 4.6 kg (10.1 lb) for the Mediterraneans, and 5.5 kg (12.1 lb) for the low-carb group.
  • Among the 45 women, the low-fat group lost only 0.1 kg (0.22 lb), the Mediterraneans lost 6.2 kg (13.6 lb), and the low-carbers lost 2.4 kg (5.3 lb).  There were only 15, 20, and 10 women in these groups, respectively.
  • All groups had significant blood pressure reductions: about 4 mmHg systolic and 1 mmHg diastolic.
  • HDL cholesterol (the “good cholesterol”) increased in all groups, 8.4 mg/dl in the low-carb group, about 6.3 in the others.
  • LDL cholesterol (the “bad cholesterol”) fell 5.6 mg/dl in the Mediterraneans, 3.0 mg/dl in the low-carbers, and none in the low-fat group.  But these were not statistically significant differences between the groups.
  • The ratio of total to HDL cholesterol decreased for all groups, but the relative 20% decrease in the low-carb group was statistically significant compared to the 12% relative decrease in the low-fat group.  The ratio fell 16% in the Mediterranean group.  [The total/HDL ratio is thought to reflect risk of developing atherosclerotic complications.  You want it under 5 to 1, and 3.5 to 1 may be ideal.]
  • The level of high-sensitivity C-reactive protein decreased significantly only in the Mediterranean and low-carb cohorts.  [C-reactive protein is felt to be a marker of the systemic inflammation that has a role in atherosclerosis or hardening of the arteries.]
  • Thirty-six of the diabetics had adequate lab studies for analysis – about 12 in each diet group.  Only those in the Mediterranean group had a significant decrease in fasting glucose – 33 mg/dl.  The low-fat group had an increase.  Glycated hemoglobin decreased in all three groups although to a significant degree (0.9%) only in the low-carb group.  [High glycated hemoglobin levels reflect poor control of blood sugar levels in diabetics.]
  • Insulin levels decreased significantly in all three groups, diabetic or not.  [Abnormally high insulin levels are felt to have adverse health effects.]

Limitations of the study

  • Relatively few women, making it difficult to reliably generalize results to women.
  • Relatively few people with diabetes, making it difficult to reliably generalize results to people with diabetes.
  • Israeli gene pool?  Results not applicable to others?
  • No change in physical activity recommended to participants.  Increased exercise should enhance weight loss.

Take-Home Points

  • Caloric restriction leads to weight loss.
  • Mild degrees of weight loss reduce blood pressure.
  • In this study, the low-carb/Atkins and Mediterranean diets were more effective than the “low-fat” diet.
  • Atkins dieters can lose weight without counting calories, by limiting carbohydrate intake.
  • You gotta wonder if the low-carb group would have been even more successful if they had actually limited carbs to 120 grams daily.
  • It’s possible a lower-fat diet may have been more efficacious than the one utilized here.
  • This study did not enroll enough women to prove that a calorie-restricted Mediterranean diet is superior to low-fat and Atkins diets.  The greater weight loss – 13.6 pounds for Mediterranean versus 5.3 with Atkins – is suggestive and requires further study.
  • The average amounts of weight loss are not much when you think about the effort expended over 24 months of intervention.
  • These dieters reportedly reduced their daily caloric intake from baseline levels by about 450 calories, over the course of two years.  Yet they lost relatively little weight.  The numbers do not jive.  Most likely there is a problem with the methodology.  I doubt the average daily calorie deficit was as high as 450.
  • The Mediterranean diet seems to have been better for the people with diabetes.  Confirmatory studies are imperative.  Insulin resistance is an important factor in type 2 diabetes.  Monounsaturated fats, which are prominent in olive oil and the Mediterranean diet, are linked to improvement in insulin resistance in other studies.
  • For people who need to lose excess fat yet refuse to consciously restrict overall caloric  intake, the low-carb Atkins diet is a reasonable option.
  • The traditional Mediterranean diet has demonstrable long-term health benefits: longer lifespan, less cancer (colon, prostate, breast, uterus), reduction of cardiovascular disease, less dementia, and prevention of type 2 diabetes.  The Atkins diet cannot make those claims in 2008.

Steve Parker, M.D.

Reference:  Shai, Iris, et al.  Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet.  New England Journal of Medicine, 359 (2008): 229-241.

Additional information and critical analysis for health nuts like me:

Dr. Dean Ornish’s analysis in Newsweek online   Dr. Ornish is a leading low-fat diet advocate.

American Heart Association comments on the study in a July 19, 2008, news release

My additional comments:

The Mediterranean diet used in this study is based on Walter Willett’s 2001 book, Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating.  From the author:

I wrote this book to show you where the USDA Pyramid is wrong and why it is wrong.  I wanted to offer a new healthy eating guide based of the best scientific evidence, a guide that fixed the fundamental flaws of the USDA Pyramid and helps you make better choices about what you eat.  I also wanted to give you the latest information on new discoveries that shuould have profound effects on our eating patterns. 

Dr. Willett made a conscious decision not to call his new eating plan a Mediterranean diet.  Elsewhere in the book he notes that the Mediterranean diet pyramid promoted by Oldways Preservation and Exchange Trust is a good, evidence-based guide for healthy eating.  The entire book promotes Harvard’s Healthy Eating Pyramid, not the Mediterranean diet per se.

Harvard’s Healthy Eating Pyramid:

Harvard's Healthy Eating Pyramid

So were the Mediterranean dieters in the study at hand even following the Mediterranean diet?  The most glaring difference is Harvard’s lack of emphasis on olive oil.  Of lesser note is Harvard’s recommendation to eat white rice, white bread, potatoes, and refined-flour pasta only sparingly.  However, the researchers for this study directed Mediterranean diet participants to ingest 30-45 grams of olive oil per day.  After comparing the Harvard pyramid with the Oldways Mediterranean pyramid and other Mediterranean diet descriptions, it is fair to say the dieters here were indeed instructed on a Mediterranean diet.  In fact, the Mediterranean diet in this study is quite similar to the Advanced Mediterranean Diet.

Traditional healthy Mediterranean diet pyramid of Oldways Preservation and Exchange Trust:

Traditional healthy Mediterranean diet pyramid of Oldways Preservation and Exchange Trust

 

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Low-Carb Diet Beats Low-Fat, Calorie-Restricted Diet

Body mass index 38

Body mass index 38

I found one of the early studies (2003) demonstrating the effectiveness and safety of an Atkins-style diet in the severely obese.  Doctors traditionally have been hesitant to recommend the Atkins diet out of concern for tolerability and potential increased atherosclerosis complication such as heart attacks, strokes, and poor circulation.

Methodology

The study enrolled 132 subjects with an average body mass index of 43, including 77 blacks and 23 women.  39% had diabetes, 43% had metabolic syndrome.  They were randomly assigned to either . . .

  1. a low-carb diet without caloric restriction (carbohydrates limited to 30 gm/day; vegetables and fruits with high ratios of fiber to carbohydrate were recommended), or
  2. a low-fat, calorie-restricted diet. 

Subjects followed their diets for six months.  The researchers never specified, but I’m assuming the diabetics were all type 2. 

Results

The drop-out rate was equally high in both groups: only 79 subjects completed the study.  The low-carb group lost 5.8 kg (13 lb); the low-fat group lost 1.9 kg (4 lb).  Analysis included the drop-outs, for reasons unclear to me.  White subjects lost more weight than blacks: 13 versus 5 kg (29 versus 11 lb).  Total cholesterol, HDL cholesterol, and LDL cholesterol levels did not change significantly within or between groups.  [HDL usually rises on a low-carb diet.]   Triglycerides fell 20% in the low-carb group and 4% in the other group.  For subjects with diabetes, glucose levels fell 26 mg/dl in the low-carb group compared to 5 mg/dl in the low-fat group.  Uric acid levels didn’t change in either group.  [Elevated uric acid levels can cause gout.]  No significant adverse reactions attibutable to the diets were recorded in either group.  Glycosylated hemoglobin fell from 7.8 to 7.2% in the low-carb group, with no change in the low-fat group.   

Take-Home Points  

It’s a small study, so results may not be very accurate or generalizable to other populations.

In this cohort with a high prevalence of diabetes, the low-carb diet was more effective than the low-fat/calorie-restricted diet for weight loss, with no adverse lipid changes to suggest increased long-term cardiovascular risk.  The low-carb diet helped control diabetes. 

Steve Parker, M.D. 

Reference:  Samaha, Frederick, et al.  A low-carbohydrate as compared with a low-fat diet in severe obesity.  New England Journal of Medicine, 348 (2003): 2,074-2,081.

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Filed under Carbohydrate, Overweight and Obesity, Weight Loss