Spanish Ketogenic Mediterranean Diet

Altea, Plaça de la EsglésiaEver 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.


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.


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 lossNutrition 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 reviewJournal 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 trialJournal 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 trialAnnals of Internal Medicine, 140 (2004): 778-785.

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


Filed under Carbohydrate, ketogenic diet, Weight Loss

11 responses to “Spanish Ketogenic Mediterranean Diet

  1. Abalone

    “Most people can follow a ketogenic diet for only two or three months. ”

    It would be interesting to see research on the reasons for dropping out. In my experience, very low-carb diets are the easiest because hunger is rare even when calories are severely restricted. I have stuck to mine for years and reaped the benefits.

    The primary obstacle that I can see is social, cultural, and practical difficulty. It’s nearly impossible to eat in a restaurant or with friends and family because our culture so favors carbs. Starches dominate most meal settings. If you have a strong need to belong, the dominant cuisine will defeat you. Not many people can sit down to Thanksgiving Dinner with friends or family and put nothing but turkey on the plate. It risks being rude to the hostess and is very isolating. Many would reflexively and subconsciously choose fitting in over health.

    Other obstacles include carb addiction/withdrawal symptoms, the nature of the foods we associate with celebration, and the official expert and government message that promotes replacing fat and meat with starches and fruits.

    No wonder people drop out.

  2. Steve Parker, M.D.

    Thanks for the insightful comments, Abalone. When I was on the Atkins program years ago, I was very disappointed when I realized I could never again eat a slice of apple pie – too many carbs. It exceeded my “maximum allowable…” something or other.

    My “sweet tooth” is something I have to work to control.

    I suspect surveys of ex-low-carb dieters would say “too restrictive” is the most popular reason for drop-out. Your explanations take it to another level.

    To those I would add, “Some carbs just plain taste too good to ignore.”

    • jenskitchen

      I really have to disagree with several points. I don’t find low-carb restrictive at all. I enjoy a variety of foods I never even thought of trying before – in some ways, my food choices are so much more varied, because low-carb got me thinking about new foods I’d never thought of before.

      Also, following a ketogenic diet for more than a couple of months. I agree that there are people out there who follow a low-carb diet like Atkins incorrectly. And, in doing so, they are setting themselves up for failure. Atkins, followed correctly, allows you to build on the basics – testing out foods to discover the right balance for you.

      As for apple pie? Why say never? Now that I am at a maintenance level (eating 120 net carbs daily plus an additional 25 net carbs of fiber), there are many possibilities. I have the occasional planned eating “adventure” and enjoy great food every day.

      And, I’ve lost 125 pounds along the way and my doctor tells me my bloodwork is “stellar” now instead of warning me of my high cholesterol.


  3. Thanks for this comprehensive review. Of course I do not work directly with diabetic patients, but with our current population statistics, I’ve seen my share due to other issues.

  4. Abalone

    Re: “some carbs just plain taste too good to ignore,” I can relate to that. Baskin Robbins’ offering of pumpkin pie ice cream was my annual undoing. And then there were kheer and truffles and pasta aglio e olio… It has been my experience, though, that after a prolonged absence the interest fades. I have even gone back after years and sampled one of my old favorites only to discover that it didn’t taste anywhere near as good as I remembered and that I wasn’t really interested in it any more.

    I have always found it easier to give up something entirely than ease off it. People vary, of course, but cold turkey is a viable strategy to try. If it works, it obviates the need to “work to control.” If it doesn’t, then one is no worse off.

    • That’s a very good point about one’s taste or desire for something fading over time. Many of my patients who have cut back on salt intake in an effort to lower their blood pressure have told me that after several months of salt restriction, they don’t miss it. On the other had, several ex-smokers tell me they still miss the cigarettes even five years after quitting. Speaking of ex-smoking and “easing off,” quitting cold turkey (all at once) is usually more effective than “just cutting back gradually.”

  5. I was wondering , Steve — since I’m in the groove — how much your diet approach may sponsor ketosis symptoms during the transition to very low carbs? I’m down there at under 30 grams/day and I feel rotten these last couple of weeks with episodes of SOB. My blood sugar on the other hand is excellent. Very stable around 5.4-5.8 mmol. So I’m wondering that for Diabetes II folk whether ketone testing is warranted as an accompaniment? But then, so what if the ketones are up: what do you do? That’s a contradiction with low carbs and diabetes, right? There has to be ‘ issues’ on occasion that may arise as the body shocks itself into a new fuel resource.

    • Hey, Dave.
      The precise cause of “induction flu” symptoms seen with many ketogenic weight-loss diets in the first one or two weeks is not entirely clear. Ketosis might play a role, as may fluid and electrolyte shifts and ezyme system adjustments. I bet other factors, some unknonw, contribute as well. “Induction flu” symptoms include weakness, fatique, headache, dizziness, poor exercise tolerance, muscle aches, etc. SOB (shortness of breaht is usually not part of it, so you had best check with your personal physician.
      I haven’t found routine urine ketone testing to be very helpful.
      Honest-to-God diabetic ketoacidosis, a true medical emergency, should not be confused with induction flu. Diabetic ketoacidosis does occasionally arise in type 2 diabetics, but isn’t typically associated with a well-designed ketogenic diet. The bloodstream ketone bodies in diabetic ketoacidosis are at least 10 times higher than levels seen in weight-loss or starvation ketosis.


  6. Ah. Surprize. Surprize. The dietary change kick started an episode of Hyperuricemia. I knew there was something toxic wafting around my system. It wasn’t until after a coupe of weeks of fever and chills that a bona fide limping ‘gout’ revealed itself.

    I re-read your transition chapters and see that I had my own patents to bring to the mix.

    I’m happy.

    How powerful is diet, right?