Tag Archives: low carb diet

Do Low-Carb Diets Cause Death?

Adult life is a battle against gravity. Eventually we all lose.

Adult life is a battle against gravity. Eventually we all lose.

Japanese researchers say low-carb diets are causing premature death. I’m skeptical.

The potentially healthful side effects linked to low-carb eating include reduced weight, higher HDL cholesterol, and lower triglycerides and blood pressure. The Japanese investigators wondered if the improved cardiovascular risk factors seen with low-carb diets actually translate into less heart disease and death.

How Was the Study At Hand Done?

The best way to test long-term health effects of a low-carb diet (or any diet) is to do a randomized controlled trial. You take 20,000 healthy and very similar people—not rodents—and randomize half of them to follow a specific low-carb diet while the other half all eat a standard or control diet. Teach them how to eat, make damn sure they do it, and monitor their health for five, 10, or 20 years. This has never been, and never will be, done in humans. The Nazis may have done it, but it’s not published. In the old days, we could do this study on inmates of insane asylums or prisons.

What we have instead are observational studies in which people voluntarily choose what they’re eating, and we assume they keep eating that way for five or 10+ years. You also assume that folks who choose low-carb diets are very similar to other people at the outset. You depend on regular people to accurately report what and how much they’re eating. You can then estimate how much of their diet is derived from carbohydrate and other macronutrients (protein and fat), then compare health outcomes of those who were in the top 10% of carb eaters with those in the bottom 10%. (We’ve made a lot of assumptions, perhaps too many.)

Of the observational studies the authors reviewed, the majority of the study participants were from the U.S. or Sweden. So any true conclusions may not apply to you if you’re not in those countries. In looking for articles, they found no randomized controlled trials.

The observational studies estimated carb consumption at the outset, but few ever re-checked to see if participants changed their diets. That alone is a problem. I don’t know about you, but I’ve had significant changes in my diet depending on when I was in college and med school, when I was a bachelor versus married, when my income was higher or lower, and when I had young children versus teenagers. But maybe that’s just me.

The researchers looked at all-cause mortality, deaths from cardiovascular disease, and incidence of cardiovascular disease. They don’t bother to define cardiovascular disease. I assume heart attack, strokes, and peripheral vascular disease. (But aren’t aneurysms, deep vein thrombosis, and pulmonary embolism vascular diseases, too?) Wouldn’t you think they’d carefully define their end-points? I would. Since they were going to all this trouble, why not look at cancer deaths, too?

What Did the Investigators Conclude?

Very low-carbohydrate dieters had a 30% higher risk of death from any cause (aka all-cause mortality) compared to very high-carb eaters. The risk of cardiovascular disease incidence or death were not linked with low-carb diets. Nor did they find protection against cardiovascular disease.

Finally, “Given the facts that low-carbohydrate diets are likely unsafe and that calorie restriction has been demonstrated to be effective in weight loss regardless of nutritional composition, it would be prudent not to recommend low-carbohydrate diets for the time being.”

If Low-Carb Dieters Die Prematurely, What Are They Dying From?

The top four causes of death in the U.S. in 2011, in order, were:

  1. heart attacks
  2. cancer
  3. chronic lower respiratory tract disease
  4. stroke

You’ll note that two of those are cardiovascular disease: heart attacks and stroke. So if low-carb diets promote premature death, it’s from cancer, chronic lung disease, or myriad other possibilities. Seventy-five percent of Americans die from one of the top 10 causes. Causes five through 10 are:

  • accidents
  • Alzheimer disease
  • diabetes
  • flu and pneumonia
  • kidney disease
  • suicide

Problem is, no one has ever linked low-carb diets to higher risk of death from any specific disease, whether or not in the top ten. Our researchers don’t mention that. That’s one reason I’m very skeptical about their conclusion. If you’re telling me low-carb diets cause premature death, tell me the cause of death.

Another frustration of mine with this report is that they never specify how many carbohydrates are in this lethal low-carb diet. Is it 20 grams, 100, 150? The typical American eats 250-300 grams of carb a day. If you’re going to sound the alarm against low-carb diets, you need to specify the lowest safe daily carb intake.

For most of my career—like most physicians—I’ve been wary of low-carb diets causing cardiovascular disease. That’s because they can be relatively high in total fat and saturated fat. In 2009, however, I did my own review of the scientific literature and found little evidence of fats causing cardiovascular disease.

If you’re looking for a reason to avoid low-carb diets, you can cite this study and its finding of premature death. I’m not convinced. I’ll turn it around on you and note this study found no evidence that low-carb diets cause cardiovascular disease. The risk of cardiovascular disease had been the traditional reason for physicians to recommend against low-carb diets.

Steve Parker, M.D.

Reference: Noto, Hiroshi et al. Low-Carbohydrate diets and all-cause mortality: A systematic review and meta-analysis of observational studies. PLoS One, 2013; 8(1): e55050

Low-Carb Beats Low-Fat Diet for Weight Loss Without Increase in Heart Disease Risk

…according to an article at MedPageToday.

Many physicians have been reluctant to recommend low-carb diets out of fear that they increase cardiovascular risk. A recent study compared low-carb to low-fat dieting over 12 months and actually found better improvements in cardiovascular disease risk factors on the low-carb diet (max of 40 grams a day).

After 12 months, folks on a low-carbohydrate diet had lost 5.3 kg (11.7 lb), while those on a low-fat diet with similar caloric value had lost 1.8 kg (3.9 lb). Both groups showed lowering of LDL cholesterol, while the low-carbers had better improvements in HDL cholesterol and triglycerides.

DietDoctor Andreas Eenfeldt can add this study to his list of others that show better weight loss with low-carb diets compared to low-fat.

Steve Parker, M.D.

Mediterranean Diet Helps With Maintenance of Weight Loss After Ketogenic Diet

Italian seaside tangentially related to this post

Italian seaside tangentially related to this post

Investigators affiliated with universities in Italy and Greece wondered about the effect on obesity of two ketogenic “Mediterranean” diet spells interspersed with a traditional Mediterranean diet over the course of one year. They found significant weight loss, and perhaps more importantly, no regain of lost weight over the year, on average.

This scientific study is right up my alley. I was excited when I found it. Less excited after I read it.

The Set-Up

This was a retrospective review of medical records of patients of a private nutritional service in three fitness and weight control centers in Italy between 2006 and 2010. It’s unclear whether patients were paying for fitness/weight loss services. 327 patient records were examined. Of these, 89 obese participants met the inclusion and exclusion criteria and started the program; 68 completed it and were the ones analyzed. (That’s not at all a bad drop-out rate for a year-long study.)  The completers were 59 males and 12 females (I know, the numbers don’t add up, but that’s what they reported). Ages were between 25 and 65. Average weight was 101 kg (222 lb), average BMI 35.8, average age 49. All were Caucasian. No diabetics.

Here’s the program:

  1. 20 days of a very-low-carb ketogenic diet, then
  2. 20 days of a low-carbohydrate non-ketogenic diet for stabilization, then
  3. 4 months of a normal caloric Mediterranean diet, then
  4. repeat #1 and #2, then
  5. 6 months of a normal caloric Mediterranean diet

In the ketogenic phases, which the authors referred to as KEMEPHY, participants followed a commercially available protocol called TISANOREICA. KEMEPHY is combination of four herbal extracts that is ill-defined (at least in this article), with the idea of ameliorating weakness and tiredness during ketosis. The investigators called this a ketogenic Mediterranean diet, although I saw little “Mediterranean” about it. They ate “beef & veal, poultry, fish, raw and cooked green vegetables without restriction, cold cuts (dried beef, carpaccio and cured ham), eggs and seasoned cheese (e.g., parmesan).” Coffee and tea were allowed. Items to avoid included alcohol, bread, pasta, rice, milk, and yogurt. “In addition to facilitate the adhesion to the nutritional regime, each subject was given a variety of specialty meals constituted principally of protein and fibers. “These meals (TISANOREICA) that are composed of a protein blend obtained from soya, peas, oats (equivalent to 18 g/portion) and virtually zero carbohydrate (but that mimic their taste) were included in the standard ration.” They took a multivitamin every morning. Prescribed carbohydrate was about 30 grams a day, with macronutrient distribution of 12% carb, 36 or 41% protein, and 51 0r 52% fat. It appears that prescribed daily calories averaged 976 (but how can that be prescribed when some food items are “unrestricted”?).

I found little explanation of period #2 mentioned above, the low-carb non-ketogenic diet. Prescribed macronutrients were 25 or 33% carb, 27 0r 31% protein, 41 or 44% fat, and about 91 g carbohydrate. Prescribed daily calories appear to have averaged 1111.

After the first and second active weight loss ketogenic phases, participants ate what sounds like a traditional Mediterranean diet. Average prescribed macronutrient distribution was 57% carbohydrate, 15 % protein, and 27% fat. Wine was allowed. It looks like 1800 calories a day were recommended.

Food consumption was measured via analysis of 3-day diaries, but you have to guess how often that was done because the authors don’t say. The results of the diary analyses are not reported.

What Did They Find?

Most of the weight loss occurred during the two ketogenic phases. Average weight loss in the first ketogenic period was 7.4 kg (16 lb), and another 5.2 kg (11 lb) in the second ketogenic period. Overall average weight loss for the entire year was 16.1 kg (35 lb).

Average systolic blood pressure over the year dropped a statistically significant 8 units over the year, from 125 to 116 mmHg.

Over the 12 months, they found stable and statistically significant drops in total cholesterol, LDL cholesterol (“bad cholesterol”), triglycerides, and blood sugar levels. No change in HDL cholesterol (“good cholesterol”).

Liver and kidney function tests didn’t change.

The authors didn’t give explanations for the drop-outs.

Although the group on average didn’t regain lost weight, eight participants regained most of it. The investigators write that “…the post dietary analysis showed that they were not compliant with nutritional guidelines given for the Mediterranean diet period. These subjects returned tho their previous nutrition habits (“junk” food, high glycaemic index, etc.) with a mean “real” daily intake of 2470 Kcal rather than the prescribed 1800 Kcal.”

Comments

A key take-home point for me is that the traditional Mediterranean diet prevented the weight regain that we see with many, if not most, successful diets.

However, most formulas for calculating steady state caloric requirements would suggest these guys would burn more than the 1800 daily calories recommended to them during the “normal calorie” months. How hard did the dieters work to keep calories around 1800? We can only speculate.

Although the researchers describe the long periods of traditional Mediterranean diet as “normal caloric,” they don’t say how that calorie level was determined  and achieved in the real world. Trust me, you can get fat eating the Mediterranean diet if you eat too much.

I’ll be the first to admit a variety of weight loss diets work, at least short-term. The problem is that people go back to their old ways of eating regain much of the lost weight, typically starting six months after starting the program. It was smart for the investigators to place that second ketogenic phase just before the typical regain would have started!

There are so few women in this study that it would be impossible to generalize results to women. Why so few? Furthermore, weight loss and other results weren’t broken down for each sex.

I suspect the results of this study will be used for marketing KEMEPHY and TISANOREICA. For all I know, that’s why the study was done. We’re trusting the investigators to have done a fair job choosing which patient charts to analyze retrospectively. They could have cherry-picked only the good ones. Some of the funding was from universities, some was from Gianluca Mech SpA (what’s that?).

How much of the success of this protocol is due to the herbal extracts and TISANOREICA, I have no idea.

The authors made no mention of the fact the average fasting glucose at baseline was 103 mg/dl (5.7 mmol/l). That’s elevated into the prediabetic range. So probably half of these folks had prediabetes. After the one-year program, average fasting glucose was normal at 95 mg/dl (5.3 mmol/l).

The improved lipids, blood sugars, and lower blood pressure may have simply reflected successful weight loss and therefore could have been achieved  by a variety of diets.

The authors attribute their success to the weight-losing metabolic effects of the ketogenic diet (particularly the relatively high protein content), combined with the traditional Mediterranean diet preventing weight regain.

The authors write:

The Mediterranean diet is associated with a longer life span, lower rates of coronary heart disease, hypercholesterolemia, hypertension, diabetes and obesity. But it is difficult to isolate the “healthy” constituents of the Mediterranean diet, since it is not a single entity and varies between regions and countries. All things considered there is no “one size fits all” dietary recommendation and for this reason we have tried to merge the benefits of these two approaches: the long term “all-life” Mediterranean diet coupled with brief periods of a metabolism enhancing ketogenic diet.

I’ve attempted a similar merger with my Low-Carb Mediterranean Diet. Click here for an outline. Another stab at it was the Spanish Ketogenic Mediterranean Diet. And here’s my version of a Ketogenic Mediterranean Diet.

Steve Parker, M.D.

Reference: Paoli, Antonio, et al. Long Term Successful Weight Loss with a Combination Biphasic Ketogenic Mediterranean Diet and Mediterranean Diet Maintenance Protocol. Nutrients, 5 (2013): 5205-5217. doi: 10.3390/nu5125205

Recipe: Naked Chicken Fajitas

paleobetic diet

It looks more appealing if you use green and red bell peppers

My earliest recollection of fajitas is from 1981 in Austin, Texas. I had just moved there from Oklahoma City to start my internship and residency in Internal Medicine at Brackenridge Hospital. Back then fajitas were made with skirt steak, the diaphragm of a cow or steer. It was considered a cheap low-quality cut of meat. You can also make fajitas with chicken. The contents of a fajita are wrapped in a tortilla usually made with flour. Are you trying to lose weight or prevent weight gain by cutting back on calories? You can do that but retain all the flavor by using lettuce as a wrapper.

Today’s recipe is very low-carb; after adding walnuts and a pear to comprise a whole meal, it’s still just 27 grams of digestible carbohydrate per serving.

I wonder if the El Azteca Restaurant in Austin is still in business. Best Mexican food I ever had. I think it was on 6th Street or so, about 3/4 mile east of I-35. Good times.

By the way, the j in fajita is pronounced “h.” Accent on second syllable. “Fuh-HEET-uh.”

Today we’re using chicken and making four servings.

paleobetic diet, paleo diet for diabetics

Pre-cut chicken breasts and sweet mini-peppers

Ingredients:

1 lb (454 kg) chicken breast, raw, boneless and skinless, cut in strips about 1/4-inch wide (you can often buy it this way)

7 oz onion, raw, cut in long crescent shapes about a 1/4-inch wide (0.6 cm)

6 oz (170 g) bell pepper, raw, cut in long strips roughly a 1/4-inch wide (these are also called sweet peppers; a combination of the red and green ones is eye-pleasing)

2 tbsp (30 ml) olive oil

5 or 6 oz (155 g) tomato, raw, cut in long strips

1 tsp (5 ml) salt

1/2 tsp (2.5 ml) pepper

1/2 tsp (2.5 ml) chili powder

1 tsp (5 ml) parsley flakes

1/2 tsp (2.5 ml) oregano leaves

1 pinch of cumin

1/2 tsp (2.5 ml) paprika

(Optional: You could replace all these spices with a 1-oz (28 g) pack of Lawry’s Chicken Fajitas Spices & Seasoning. The sodium and potassium values below would be different.)

1/3 cup (80 ml) water

16 oz (454 g) lettuce (e.g., iceberg, romaine, or bibb)

4 oz (113 g) walnuts

4 pears, small (about 1/3 lb or 150 g each))

Instructions:

Add the onions, peppers, and 1 tbsp (15 ml)  olive oil to a 12-inch (30 cm) skillet and cook at medium-high heat until tender, stirring occasionally. This’ll take about 10 minutes. Set the skillet contents aside.

paleobetic diet, paleo diet for diabetes

This is double the recipe amount since there are six humanoids in my household

paleobetic diet, paleo diet for diabetics

The vegetables reduce volume by half while cooking

In the same pan, add 1 tbsp (15 ml) olive oil and the chicken and cook at medium to medium-high heat, stirring frequently, until chicken is thoroughly cooked. For me, this cooked quicker than the vegetables. But don’t overcook or the chicken will get tough. Then add the water and all the spices. Bring to a boil while stirring occasionally, then simmer on low heat a few minutes. This is your fajita filling.

My original plan was to make “fajita wraps,” wrapping the cooked fajitas into a large leaf of iceberg lettuce. This was pretty messy, especially since I love the sauce in the bottom of the pan. I tried two leafs as a base: still messy. Finally I just made a bed of lettuce (4 oz) and loaded the fajita concoction right on top. Mess gone. Try a different lettuce? Skip the lettuce entirely and you can reduce digestible carb count in each serving by 2 grams.

Enjoy the walnuts and pear with your meal.

Leftovers taste just as good as fresh-cooked, perhaps even better.

I have another fajita recipe using skirt steak marinated in commercial Zesty Italian Dressing in the refrigerator overnight or for at least four hours. Grill it over coals outside. Yum! I don’t recall whether I added lemon juice to the marinade or squirted it on the meat just before serving. You would just cook the onions and peppers on a pan on the stove as above, with salt and pepper to taste. Garnish with a margarita and I’ll make you an honorary Texan.

Number of servings: 4

Serving size: A cup (240 ml) of the fajita mixture, 4 oz (113 g) lettuce, 1 oz (28 g) walnuts, 1 small pear. One cup makes two lettuce wraps.

Nutritional Analysis Per Serving:

48% fat

26% carbohydrate

26% protein

Calories: 514

37 g carbohydrate

10 g fiber grams

27 g digestible carbohydrate (25 g if you skip the lettuce)

928 mg sodium

904 mg potassium

Prominent features: Rich in protein, vitamin B6, vitamin B12, vitamin C,copper, iron, manganese, niacin, phosphorus, and selenium.

paleobetic diet

Another view, prior to rolling it up (wrapping)

Why Do So Many Dietitians Argue Against Low-Carb Diets?

Click for details from dietitian Franziska Spritzler. Briefly:

1. They think it’s dangerous. 
2.They believe the diet-heart hypothesis
3. They think the diet is unbalanced.  
4. They think no one will follow it long term.

Franziska ably debunks these ideas one by one.

Low-Carb Ketogenic Diet Appears Safe and Effective for Children and Adolescents

A ketogenic diet was safe and effective for weight loss in children and adolescents, according to a small study in the Journal of Pediatric Endocrinology and Metabolism.  Fifty-six children were placed on either a ketogenic diet or a calorie-restricted diet.  The investigators judged the low-carb ketogenic diet more effective.

I don’t treat children, so I don’t normally follow the pediatric scientific literature.  Thanks to Diet Doctor Andreas Eenfeldt for bringlng this to my attention.  I’ve not read the full research report.

In 2010 I reported on research showing a low-carb, high-protein diet was safe and effective for severely obese adolescents.

Study Finds Low-Carb Diet Reduces Heart Disease Risk Factors

Obesity Reviews just published details of a recent meta-analyis of low-carbohydrate diet effects on cardiovascular risk factors.

A systematic review and meta-analysis were carried out to study the effects of low-carbohydrate diet (LCD) on weight loss and cardiovascular risk factors (search performed on PubMed, Cochrane Central Register of Controlled Trials and Scopus databases). A total of 23 reports, corresponding to 17 clinical investigations, were identified as meeting the pre-specified criteria.

Over a thousand obese patients were involved.  By eating low-carb, blood pressure dropped by 3–4 mmHg, average body weight decreased by 7 kg (15 lb), body mass index dropped by 2, triglycerides decreased by 30 mg/dl, hemoglobin A1c dropped by 0.21% (absolute decrease), insulin levels fell by 2.23 micro IU/ml, while HDL cholesterol rose by 1.73 mg/dl.  LDL cholesterol didn’t change.

The authors conclusion:

Low-carboydrate diet was shown to have favourable effects on body weight and major cardiovascular risk factors; however the effects on long-term health are unknown.

I haven’t see the full text of the article yet, so I don’t know the carbohydrate level under review.  I bet it’s under 50 g of digestible carb daily.  My Low-Carb Mediterranean Diet starts at 20-30 grams a day.

Steve Parker, M.D.

Reference:  Santos, F.L., et al. Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors. Obesity Reviews. Article first published online: 20 AUG 2012. DOI: 10.1111/j.1467-789X.2012.01021.x