Diabetic Mediterranean Diet

Ever heard of the Spanish Ketogenic Mediterranean Diet?  It looks like a low-carb quasi-Mediterranean diet.

Researchers with the University of Cordoba in Spain studied 40 subjects eating a low-carb “Mediterranean” diet for 12 weeks.  The results were strikingly positive.

Methodology

A medical weight loss clinic was the source of 40 overweight subjects, 22 males and 19 females, average age 38, average body mass index 36.5, average weight 108.6 kg (239 lb).  These folks were interested in losing weight, and were not paid to participate.

Nine subjects were not included in the final analysis due to poor compliance with the study protocol (3), the diet was too expensive (1), a traumatic car wreck (1), or were simply lost to follow-up (4).  So all the data are pooled from the 31 subjects who completed the study.

Blood from all subjects was drawn just before the study began and again after 12 weeks of the diet.

Study diet:  Low-carbohydrate, high in protein [and probably fat, too], unlimited in calories.  Olive oil was the main source of fat (at least 30 ml daily).  Maximum of 30 grams of carbohydrates daily as green vegetables and salad.  200-400 ml daily of red wine.  The authors write:

Participants were permitted 3 portions (200 g/portion) of vegetables daily: 2 portions of salad vegetables (such as alfalfa sprouts, lettuce, escarole, endive, mushrooms, radicchio, radishes, parsley, peppers, chicory, spinach, cucumber, chard and celery), and 1 portion of low-carbohydrate vegetables (such as broccoli, cauliflower, cabbage, artichoke, eggplant, squash, tomato and onion).  3 portions of salad vegetables were allowed only if the portion of low-carbohydrate vegetables were not consumed.  Salad dressing allowed were: garlic, olive oil, vinegar, lemon juice, salt, herbs and spices.

The minimum 30 ml of olive oil were distributed unless in 10 ml per principal meal (breakfast, lunch and dinner).  Red wine (200–400 ml a day) was distributed in 100–200 ml per lunch and dinner.  The protein block was divided in “fish block” and “no fish block”.  The “fish block” included all the types of fish except larger, longer-living predators (swordfish and shark).  The “no fish block” included meat, fowl, eggs, shellfish and cheese.  Both protein blocks were not mixed in the same day and were consumed individually during its day on the condition that at least 4 days of the week were for the “fish block”.

Trans fats (margarines and their derivatives) and processed meats with added sugar were not allowed.

Vitamin and mineral supplements were given.

Subjects measured their ketosis state every morning with urine ketone strips.

Results (averaged)

• Body weight fell from 108.6 kg (239 lb) to 94.5 kg (209 lb), or 2.5 pounds per week
• Body mass index fell from 36.5 to 31.8
• Systolic blood pressure fell from126 to 109 mmHg
• Diastolic blood pressure fell from 85 to 75 mmHg
• Total cholesterol fell from 208 to 187 mg/dl
• LDL chol fell from 115 to 106 mg/dl
• HDL chol rose from 50 to 55 mg/dl
• Fasting glucose dropped from 110 to 93 mg/dl
• Triglycerides fell from 219 to 114 mg/dl
• No significant differences in male and female subjects
• No adverse reactions are mentioned

Researchers’ Conclusions

The SKMD [Spanish Ketogenic Mediterranean Diet] is safe, an effective way of losing weight, promoting non-atherogenic lipid profiles, lowering blood pressure and improving fasting blood glucose levels.  Future research should include a larger sample size, a longer term use and a comparison with other ketogenic diets.

My Comments

The researchers called this diet “Mediterranean” based on olive oil, red wine, fish, and vegetables.

What’s “Not Mediterranean” is the paucity of carbohydrates (including whole grains); lack of yogurt, nuts, and legumes; and the high meat/protein intake.

The emphasis on olive oil, red wine, and fish could make this healthier than other ketogenic diets.

Ketogenic diets are notorious for high drop-out rates compared to other diets.  Most people can follow a ketogenic diet for only two or three months.  But several studies suggest greater short-term weight loss for people who stick with it.  Efficacy and superiority are little different from other diets as measured at one year out.

Many of the metabolic improvements seen here might be duplicated with loss of 30 pounds (13.6 kg) over 12 weeks using any reasonable diet.

Average fasting blood sugars in these subjects was 109 mg/dl.  Although not mentioned by the authors, this is in the prediabetes range.  The diet reduced average fasting blood sugar to 93, which would mean resolution of prediabetes.  Dropping body mass index from 36 to 32 by any method would tend to cure prediabetes.

Elevated blood sugar is one component of the “metabolic syndrome.”  Metabolic syndrome was recently shown to be reversible with a Mediterranean diet supplemented with nuts.

I suspect this would be a good program for an overweight person with uncontrolled type 2 diabetes, too.  But it has never been studied in a diabetic population.  So, who knows for sure?

If you’re thinking about doing something like this, get more information and be sure to get your doctor’s approval first.

Steve Parker, M.D.

Addendum:

On April 6, 2008, I had a delightful conversation with Jimmy Moore, of Livin’ La Vida Low-Carb fame regarding this study.  It struck me that the Spanish Ketogenic Mediterranean Diet is probably higher in protein and lower in fat than many other ketogenic weight-loss diets.  Since fish is emphasized over other animal-derived foods, it’s likely also lower in saturated fat.  [In low-carb diets, carbohydrates are substituted with either fats or proteins.]  I’m also convinced I will eventually have to review the validity of the dogmatic diet-heart hypothesis:  Dietary saturated fat, total fat, and cholesterol contribute to atherosclerosis and associated premature death from heart attacks and strokes.

References and Additional Reading:

Perez-Guisado, J., Munoz-Serrano, A., and Alonso-Moraga, A.  Spanish Ketogenic Mediterranean diet: a healthy cardiovascular diet for weight loss.  Nutrition Journal, 2008, 7:30.   doi:10.1186/1475-2891-7-30

Bravata, D.M., et al.  Efficacy and safety of low-carbohydrate diets: a systematic review.  Journal of the American Medical Association, 289 (2003): 1,837-1,850.

Gardner, C.D., et al.  Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial.  Journal of the American Medical Association, 297 (2007): 696-677.

Stern, L., et al.  The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial.  Annals of Internal Medicine, 140 (2004): 778-785.

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