Category Archives: Dietary Carbohydrate

Long-Term T2 Diabetes Diet Trial: Low-Carb Edges Out High-Carb Eating

Paleo-compliant low-carb meal. I almost used this for my Paleobetic Diet book cover.

Paleo-compliant low-carb meal. I almost used this for my Paleobetic Diet book cover.

This is an important report because most diet studies last much less than one year. Details are in the American Journal of Clinical Nutrition.

Study participants were 115 obese (BMI 35) type 2 diabetics with hemoglobin A1c averaging 7.3%. Average age was 58. So pretty typical patients, although perhaps better controlled than average.

They were randomized to follow for 52 weeks either a very low-carbohydrate or a high-carbohydrate “low-fat” diet. Both diets were designed to by hypocaloric, meaning that they provided fewer calories than the patients were eating at baseline, presumably with a goal of weight loss. The article abstract implies the diets overall each provided the same number of calories. They probably adjusted the calories for each patient individually. (I haven’t seen the full text of the article.) Participants were also enrolled in a serious exercise program: 60 minutes of aerobic and resistance training thrice weekly.

Kayaking is an aerobic exercise if done seriously

Kayaking is an aerobic exercise if done seriously

The very low-carb diet (LC diet) provided 14% of total calories as carbohydrate (under 50 grams/day). The high-carb diet (HC diet) provided 53% of total calories as carbohydrate and 30% of calories as fat. The typical Western diet has about 35% of calories from fat.

Both groups lost weight, about 10 kg (22 lb) on average. Hemoglobin A1c, a reflection of glucose control over the previous three months, dropped about 1% (absolute reduction) in both groups.

Compared to the HC diet group, the LC dieters were able to reduce more diabetes medications, lower their triglycerides more, and increase their HDL cholesterol (“good cholesterol”). These triglyceride and HDL changes would tend to protect against heart disease.

SO WHAT?

You can lose weight and improve blood sugar control with reduced-calorie diets—whether very low-carb or high-carb—combined with an exercise program. No surprise there.

I’m surprised that the low-carb group didn’t lose more weight. I suspect after two months of dieting, the low-carbers started drifting back to their usual diet which likely was similar to the high-carb diet. Numerous studies show superior weight loss with low-carb eating, but those studies are usually 12 weeks or less in duration.

diabetic diet, low-carb diet, paleobetic diet

Low-Carb Brian Burger and Bacon Brussels Sprouts (in the Paleobetic Diet)

The low-carb diet improved improved lipid levels that might reduce risk of future heart disease, and allowed reduction of diabetes drug use. Given that we don’t know the long-term side effects of many of our drugs, that’s good.

If I have a chance to review the full text of the paper, I’ll report back here.

Steve Parker, M.D.

Reference: Jeannie Tay, et al. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial. First published July 29, 2015, doi: 10.3945/​ajcn.115.112581    Am J Clin Nutr

Are Low-Carb Diets Lethal?

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

Adult life is a battle against gravity.

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

It’s a critically important issue because many folks with diabetes restrict their carbohydrate consumption to keep their blood sugars under control. Maybe it’s crazy, but they think they’ll live longer and have fewer diabetes complications if their glucose readings are under 200 mg/dl (11.1 mmol/l) most of the time.

The potentially healthful side effects linked to low-carb eating include reduced weight, higher HDL cholesterol, and lower triglycerides and blood pressure. The aforementioned 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. 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, are:

  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 major 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 carbohydrate-restricted 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

Listen to Low-Carb Diet Proponents Franziska Spritzler and Dr. Troy Stapleton

Who says low-carb paleo diets are mostly meat?

Who says low-carb paleo diets are mostly meat?

Jimmy Moore posted an interview with Dr. Troy Stapleton and Franziska Spritzler, R.D. These two wouldn’t consider themselves paleo diet gurus by any means. They advocate carbohydrate-restricted diets for management of blood sugars in diabetes, consistent with my approach in the Paleobetic Diet. Dr. Stapleton might argue I allow too many carbohydrates. By the way, he has type 1 diabetes; I’ve written about him before. Franziska is available for consultation either by phone, Skype, or in person.

Steve Parker, M.D.

Very-Low-Carb Diet Beats Medium-Carb ADA Diet in Type 2 Diabetes

Compared to a traditional American Diabetes Association diet, a very-low-carbohydrate ketogenic diet was more effective at controlling type 2 diabetes and prediabetes, according to University of California San Francisco researchers.

The debate about the best diet for people with diabetes will continue to rage, however. You’ll even find some studies supporting vegetarian diets. I’m still waiting for published results of the Frassetto group’s paleo diet trial.

Some non-starchy low-carb vegetables

Some non-starchy low-carb vegetables

Details

Thirty-four overweight and obese type 2 diabetics (30) and prediabetics (4) were randomly assigned to one of the two diets:

  1. MCCR: American Diabetes Association-compliant medium-carbohydrate, low-fat, calorie-resticted carb-counting diet. The goals were about 165 grams of net carbs daily, counting
    carbohydrates, an effort to lose weight by eating 500 calories/day less than needed for maintenance, and 45–50% of total calories from carbohydrate. Protein gram intake was to remain same as baseline. (Note that most Americans eat 250–300 grams of carb daily.)
  2. LCK: A very-low-carbohydrate, high-fat, non-calorie-restricted diet aiming for nutritional ketosis. It was Atkins-style, under 50 grams of net carbs daily (suggested range of 20–50 g). Carbs were mostly from non-starchy low-glycemic-index vegetables. Protein gram intake was to remain same as baseline.

Baseline participant characteristics:

  • average weight 100 kg (220 lb)
  • 25 of 34 were women
  • average age 60
  • none were on insulin; a quarter were on no diabetes drugs at all
  • most were obese and had high blood pressure
  • average hemoglobin A1c was about 6.8%
  • seven out of 10 were white

Participants followed their diets for three months and attended 13 two-hour weekly classes. Very few dropped out of the study.

Results

Average hemoglobin dropped 0.6% in the LCK group compared to no change in the MCCR cohort.

A hemoglobin A1c drop of 0.5% or greater is considered clinically significant. Nine in the LCK group achieved this, compared to four in the MCCR.

The LCK group lost an average of 5.5 kg (12 lb) compared to 2.6 kg (6 lb) in the MCCR. The difference was not statistically significant, but close (p = 0.09)

44% in the LCK group were able to stop one or more diabetes drugs, compared to only 11 % in the other group

31% in the LCK cohort were able to drop their sulfonylurea, compared to only 5% in the MCCR group.

By food recall surveys, both groups reported lower total daily caloric intake compared to baseline. The low-carbers ended up with 58% of total calories being from fat, a number achieved by reducing carbohydrates and total calories and keeping protein the same. They didn’t seem to increase their total fat gram intake;

The low-carbers apparently reduced daily carbs to an average of 58 grams (the goal was 20-50 grams).

There were no differences between both groups in terms of C-reactive protein (CRP), lipids, insulin levels, or insulin resistance (HOMA2-IR). Both groups reduced their CRP, a measure of inflammation.

LCK dieters apparently didn’t suffer at all from the “induction flu” seen with many ketogenic diets. They reported less heartburn, less aches and pains, but more constipation.

Hypoglycemia was not a problem.

If I recall correctly, the MCCR group’s baseline carb grams were around 225 g.

Bottom Line

Very-low-carb diets help control type 2 diabetes, help with weight loss, and reduce the need for diabetes drugs. An absolute drop of 0.6% in hemoglobin A1c doesn’t sound like much, translating to blood sugars lower by only 15–20 mg/dl (0.8–1 mmol/l). But remember the comparator diet in this study was already mildy to moderately carbohydrate-restricted. At least half of the type 2 diabetics I meet still tell my they don’t watch their carb intake, which usually means they’re eating around 250–300 grams a day. If they cut down to 58 grams, they most likely will see more than a 0.6% drop in hemoglobin A1c after switching to a very-low-carb diet.

If you’re developing a new diabetes drug that drops hemoglobin A1c by 0.6%, you’ll get FDA approval for effectiveness.

This is a small study, so it may not be reproducible in larger clinical trials and other patient populations. Results are consistent with several other similar studies I’ve seen, however.

Steve Parker, M.D.

Reference: Saslow, Laura, et al (including Stephen Phinney). A Randomized Pilot Trial of a Moderate Carbohydrate Diet Compared to a Very Low Carbohydrate Diet in Overweight or Obese Individuals with Type 2 Diabetes Mellitus or PrediabetesPLoS One. 2014; 9(4): e91027. Published online Apr 9, 2014. doi: 10.1371/journal.pone.0091027     PMCID: PMC3981696

PS: When I use “average” above, “mean” is often a more accurate word, but I don’t want to have to explain the differences at this time.

PPS: Carbsane Evelyn analyzed this study in greater detail that I did and came to different conclusions. Worth a read if you have an extra 15 minutes.

Low-Carb Diet Works in Japanese With Type 2 Diabetes

Mt. Fuji in Japan

Mt. Fuji in Japan

I don’t know much about Japanese T2 diabetes. I’ve never studied it. Their underlying physiology may or may not be the same as in North American white diabetics, with whom I am much more familiar. Physiologic differences are suggested by the fact that Japanese develop type 2 diabetes at lower BMIs (body mass index) than do Western caucasians.

For what it’s worth, a small study recently found improvement of blood sugar control and triglycerides in those on a carbohydrate restricted diet versus a standard calorie-restricted diet.

Only 24 patients were involved. Half were assigned to eat low-carb without calorie restriction; the other half ate the control diet. The carbohydrate-restricted group aimed for 70-130 grams of carb daily, while eating more fat and protein than the control group. The calorie-restricted guys were taught how to get 50-60% of calories from carbohydrate and keep fat under 25% of calories. At the end of the six-month study, the low-carbers were averaging 125 g of carb daily, compare to 200 g for the other group. By six months, both groups were eating about the same amount of calories.

Average age was 63. Body mass index was 24.5 in the low-carb group and 27 in the controls. All were taking one or more diabetes drugs.

The calorie-restricted group didn’t change their hemoglobin A1c (a standard measure of glucose control) from 7.7%. The low-carb group dropped their hemoglobin A1c from 7.6 to 7.0% (statistically significant). The low-carb group also cut their triglycerides by 40%. Average weights didn’t change in either group.

Bottom Line

This small study suggests that mild to moderate carbohydrate restriction helps control diabetes in Japanese with type 2 diabetes. The improvement in hemoglobin A1c is equivalent to that seen with initiation of many diabetes drugs. I think further improvements in multiple measures would have been seen if carbohydrates had been restricted even further.

Steve Parker, M.D.

Link to reference.

h/t Dr Michael Eades

What’s Pure, White, and Deadly?

Sugar, according to John Yudkin and Robert Lustig, among others. The Age has the details. A quote:

[Robert] Lustig is one of a growing number of scientists who don’t just believe sugar makes you fat and rots teeth. They’re convinced it’s the cause of several chronic and very common illnesses, including heart disease, cancer, Alzheimer’s and diabetes. It’s also addictive, since it interferes with our appetites and creates an irresistible urge to eat.

This year, Lustig’s message has gone mainstream; many of the New Year diet books focused not on fat or carbohydrates, but on cutting out sugar and the everyday foods (soups, fruit juices, bread) that contain high levels of sucrose. The anti-sugar camp is not celebrating yet, however. They know what happened to Yudkin and what a ruthless and unscrupulous adversary the sugar industry proved to be.

In 1822, we in the U.S. ate 6.2 pounds of sugar per person per year. By 1999, we were up to 108 pounds.

An occasional teaspoon of sugar probably won't hurt you

An occasional teaspoon of sugar probably won’t hurt you

The U.S. Department of Agriculture estimates that added sugars provide 17% of the total calories in the average American diet.  A typical carbonated soda contain the equivalent of 10 tsp (50 ml) of sugar.  The average U.S. adult eats 30 tsp  (150 ml) daily of added sweeteners and sugars.

On the other hand, Fanatic Cook Bix found a study linking higher sugar consumption with lower body weight, which you might think would protect against type 2 diabetes, heart disease, and some cancers.

Read the rest at The Age. It’s mostly about John Yudkin.

Steve Parker, M.D.

h/t Jamie Scott

Has Carbohydrate-Restricted Eating Been Studied in Type 1 Diabetes?

Sweden has lots of blondes

Sweden has lots of blondes

Yes, there are few published scientific reports. Let’s take a close look at one today. (See the references below for more.)

In the introduction to the study at hand, the authors note:

The estimation of the amount of carbohydrates in a meal has an error rate of 50%. The insulin absorption may vary by up to 30%. It is therefor virtually impossible to match carbohydrates and insulin which leads to unpredictable blood glucose levels after meals. By reducing the carbohydrates and insulin doses the size of the blood glucose fluctuations can be minimized. The risk of hypoglycemia is therefore minimized as well. Around-the-clock euglycemia [normal blood sugar] was seen with 40 g carbohydrates in a group of people with type 1 diabetes [reference #2 below].

The immediate resulting stable, near-normal blood glucose levels allow individuals to predict after-meal glucose levels with great accuracy.

For individuals with type 1 diabetes one year audit/evaluation of group education in this regimen has shown that the short-time lowering of mean hemoglobin A1c by 1 percentage unit and the reduction in mean rate of symptomatic hypoglycemia by 82% was maintained [reference #3].

***

There is no evidence for the use of the widely recommended high-carbohydrate, low-fat diet in type 1 diabetes.

Study Set-Up

Swedish investigators educated study participants on carbohydrate-restricted eating from 2004 to 2006 [reference #1]. They recently audited their medical records for results accumulated over four years. At the outset, participants were given 24 hours of instruction over four weeks. My sense is that they all attended the same diabetes clinic. The subjects’ mean age was 52 years and they had diabetes for an average of 24 years. Seven had gastroparesis. Fourteen used insulin pumps. Of the 48 study subjects, 31 were women, 17 were men. The diet regimen restricted carbohydrates to a maximum of 75 grams a day, mainly by reducing starchy food.

Results

As measured three months after starting the diet, HDL-cholesterol rose and triglycerides fell to a clinically significant degree (p<0.05). Average weight fell by 2.7 kg (5.9 lb); average baseline weight was 77.6 kg (171 lb). Hemoglobin A1c fell from 7.6 to 6.3% (Mono-S method).

As measured one year after start, meal-time insulin (rapid-acting, I assume) fell from 23 to 13 units per day. Long-acting insulin was little changed at around 19 units daily.

By two years into the study, half the participants had stopped adhering to the diet. The remainder were adherent (13 folks) or partly adherent (10). We don’t know what the non-adherents were eating.

Four years out, the adherent group had hemoglobin A1c of 6.0%, and the partly adherents were at 6.9% (p<0.001 for both). The non-adherent group had returned to their baseline HgbA1c (7.5%). Remember, at baseline the average HgbA1c for the group was 7.6%.

The authors don’t say how many participants were still adherent after four years. From Figure 2, adherence seems to have been assessed at 60 months: 8 of the 13 adherent folks were still adherent, and 5 of the 10 partly adherent were still in the game. So, of 48 initial subjects, only 13 were still low-carbing after five years later. By five years out, half of all subjects seem to have been lost to follow-up. So the drop-out rate for low-carbers isn’t as bad as it looks at first blush.

Conclusion

The authors write:

An educational program involving a low-carbohydrate diet and correspondingly reduced insulin doses for informed individuals with type 1 diabetes gives acceptable adherence after 4 years. One in two people attending the education achieves a long-term significant HbA1c reduction.

They estimate that this low-carb diet “may be an option for 10-20% of the patients with type 1 diabetes.” Only 17% of their current diabetes clinic population is interested in this low-carb diet. They didn’t discuss why patients abandon the diet or aren’t interested in the first place. Use your imagination.

Major carbohydrate restriction in type 1 diabetics significantly improves blood sugar control (decreases HgbA1c), lowers insulin requirements, and improves cardiovascular disease risk factors (increases HDL cholesterol and lowers triglycerides).

Paleo diets vary in total carbohydrate grams and percentage of calories derived from carbohydrate. Paleo diets tend to be lower in carb than usual Western diets, with 30% of total calories from carbohydrate probably a good rough estimate. The typical American eats 250 to 300 grams of carbohydrate daily, or about 50% of total calories. In the study at hand, the daily carb gram goal was 75, which would be 15% of calories for someone eating 2,000 cals/day.

Low-carb eating wasn’t very appealing to Swedes in the mid-2000s. I wonder if it’s more popular now with the popularity of LCHF dieting (low-carb, high-fat) in the general population there.

Steve Parker, M.D.

References:

1.  Nielson, J.V., Gando, C., Joensson, E., and Paulsson, C. Low carbohydrate diet in type 1 diabetes, long-term improvement and adherence: A clinical audit. Diabetology & Metabolic Syndrome, 2012, 4:23. http://www.dmsjournal.com/content/4/1/23

2.  O’Neill, D.F., Westman, E.C., and Bernstein, R.K. The effects of a low-carbohydrate regimen on glycemic control and serum lipids in diabetes mellitus. Metabolic Syndrome and Related Disorders, 2003, 1(4): 291-298.

3.  Nielsen, J.V., Jönsson, E. and Ivarsson, I. A low carbohydrate diet in type 1 diabetes: clinical experience – A brief report. Upsala Journal of Medical Sciences, 2005, 110(3): 267-273.

Physician With Type 1 Diabetes Thriving on Low-Carb Paleo-Style Diet

"Put down the bread and no one will get hurt!"

Could you give up bread for life?

ABC Radio provides the audio and transcript of an interview with Dr. Troy Stapleton, who was diagnosed with type 1 diabetes at age 41. He lives in Queensland, Australia. At the time of his diagnosis, he says…

I was advised to eat seven serves of bread and cereals, two to three serves dairy, fruit, starchy vegetables, and to balance that intake with insulin. If you add up all those serves, they were recommending a diet of up to about 240 grams of carbohydrates a day, and to balance it with insulin. I was going to be the best patient, and there has been some important trials that show that if you do control your blood glucose well then you can reduce your incidence of the complications.

Dr. Stapleton believes we evolved on a very low carbohydrate diet; the Agricultural Revolution led to our current high carb consumption. He was concerned about the risk of hypoglycemia with standard diabetic diets.

There was a different approach where essentially you went on a very low carbohydrate diet, this made a little bit of sense to me. Why would I eat carbohydrates and then have to balance it with insulin?

Here’s what the diabetes educators told him:

What they say is you need to estimate the amount of carbohydrate you’re going to eat, and then you need to match that carbohydrate dose essentially with an insulin dose. So you sort of look at your food and you go, okay, I’m having 30 grams of carbohydrate and I need one unit of insulin per 15 grams of carbohydrate, so two units. It sounds really quite straightforward, except that it’s very, very difficult to estimate accurately the amount of carbohydrate you’re eating. The information on the packets can be out by 20%. Most people say that your error rate can be around 50%.

And then of course it changes with what you’ve eaten. So if you eat carbohydrates with fat and then you get delayed absorption, then that glucose load will come in, and then the type of carbohydrates will alter how quickly it comes in to your bloodstream. And then of course your insulin dose will vary, your absorption rate will vary by about 30%. Once you think through all the variables, it’s just not possible. You will be able to bring your blood glucose under control, but a lot of the time what happens is you get a spike in your glucose level immediately after a meal, and that does damage to the endothelium of your blood vessels…

Norman Swan: The lining.

Troy Stapleton: That’s correct, it causes an oxidative stress to your endothelium, and that is the damage that diabetes does, that’s why you get accelerated atherosclerosis.

Here’s what happened after he started eating very low carb:

It’s been amazing, it’s been the most remarkable turnaround for me and I just cut out carbohydrates essentially completely, although I do get some in green leafy vegetables and those sorts of things. My blood sugar average on the meter has gone from 8.4 [151 mg/dl] down to 5.3 [95 mg/dl]. My HbA1c is now 5.3, which is in the normal range. My blood pressure has always been good but it dropped down to 115 over 75. My triglycerides improved, my HDL improved, so my blood lipid profile improved. And I would now have a hypoglycaemic episode probably about once a month after exercise. [He was having hypoglycemia weekly on his prior high carb diet with carb counting insulin adjustments.]

He was able to reduce his insulin from about 27 units a day down to 6 units at night only (long-acting insulin)! He admits his low insulin dose may just reflect the “honeymoon period” some type 1s get early on after diagnosis.

Norman Swan: So when you talk to your diabetes educator now, what does he or she say?

Troy Stapleton: Look, they’re interested, but they’ll tell me things and I’ll say, well, that’s actually not true. I’m quite a difficult patient, Norman.

He says he’s eating an Atkins-style diet. Combining the transcript and his notes in the comments section:  1) he doesn’t eat potatoes or other starchy vegetables or bread, 2) he eats meat, eggs, lots of non-starchy vegetables, some berries and tree nuts, olives, and cheese, 3) an occasional wine or low-carb beer, 4) coffee, and 5) he eats under 50 g/day of carbohydrate, probably  under 30 g. This is a low-carb paleo diet except for the cheese, alcohol, and coffee.  Cheese, alcohol and coffee are (or can be) low-carb, but they’re not pure paleo.

He notes that…

There is an adaption period to a very low carbohydrate diet which takes 4–6 weeks (ketoadaption). During this time symptoms include mild headaches, lethargy, cramps, carb cravings and occasional light headedness. These symptoms all pass.

Read or listen to the whole thing. Don’t forget the comments section. All the blood sugars you see there are in mmol/l; convert them to mg/dl (American!) by multiplying by 18.

Steve Parker, M.D.

Fermentable Carbohydrates May Cause or Aggravate Irritable Bowel Sydrome

"Dr. Parker, what can I do about these severe belly cramps?"

“Dr. Parker, what can I do about these severe belly cramps?”

Irritable bowel syndrome (IBS) is one of the conditions that allegedly improves with a paleo diet. It’s frustrating for sufferers and their doctors. My ears perk up when I hear about a new treatment.       

Four weeks of fermentable carbohydrate restriction reduces symptoms of irritable bowel syndrome, according to UK and Australian researchers.

Here’s the theory of how it works.  Our intestines—colon, mostly—are loaded with bacteria.  The food you feed your bacteria—fermentable carbohydrates, for example—may have an effect on the bacteria.  Changes in bacterial populations in response to feeding, in turn, may lead to changes in irritable bowel syndrome and other aspects of health.  This “gut microbiome” is a hot area of research and speculation.

I don’t have irritable bowel syndrome (IBS), but did notice a major decrease in gastrointestinal gas production when I reduced my digestible carbohydrate consumption to less than 50 g/day a few years ago. That alone has at least potential to reduce IBS symptoms. (I eat more than 50 g a day now.)

IBS is extremely common, affecting 10–15% of individuals in the developed world.  Only 15% of those bother to seek medical attention.   Of all referrals to gastroenterologists (stomach specialists), at least 25% are for IBS.  There are few reliable treatments and cures.  In some cases it mysteriously resolves on its own.

So I got excited when I ran across the study I reference above.  I’m not going to spend a lot of time on it because I’ve already spent too much trudging through the article, and I don’t have much to show for it.

The way the investigators wrote their report gave me some heartburn:

  • They never bothered to define “fermentable.”  In this context it probably refers to digestion or breakdown of food by gut bacteria rather than by human hosts.
  • They never bother to spell out exactly what foods the experimental subjects were eating as they restricted fermentable carbohydrate consumption.
  • The intervention group (n=19) was instructed to restrict foods “high in fructans (e.g., wheat products, onions), galacto-oligosaccharide (e.g., legumes), polyols (e.g., pear, sugar-free gums), lactose (e.g., mammalian milk), and excess fructose (e.g., honey).”  Does “restrict” mean “cut back a little” or “avoid entirely upon penalty of death”?  Your guess is as good as mine.  (It’s a joke—I know they wouldn’t kill’em.) Some of the aforementioned foods are restricted or forbidden on the paleo diet.

Have you heard of FODMAPs?  That seems to be the intervention diet that restricted fermentable carbohydrates. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.

You need a break. Enjoy.

You need a break. Enjoy.

Let me summarize their results simply by saying they found changes in gut bacteria and a reduction in irritable bowel syndrome symptoms, as compared with control subjects. The particularly responsive symptoms were bloating, borborygmi, and the urge to defecate. Abdominal pain strongly tended to improve but didn’t quite reach statistical significance. Diarrhea wasn’t affected. Also note that the IBS patients allowed into the study were not the type with constipation as a major issue.

So What? 

If you want to try a FODMAP diet for your IBS, you won’t be able to figure out what to eat based on this report. Consult your own physician about it.  I wonder whether many of them have even heard of FODMAP. Barbara Bolen, Ph.D., at About.com says the diet should be undertaken only with the supervision of a qualified nutritionist.

BTW, I’m not aware of any scientific reports looking at the paleo diet as a treatment for IBS. If it works for you, stick with it.

Steve Parker, M.D.

Reference:  Staudacher, Heidi, et al.  Fermentable Carbohydrate Restriction Reduces Luminal Bifidobacteria and Gastrointestinal Symptoms in Patients with Irritable Bowel Syndrome.  Journal of Nutrition, 142: 1520-1518 (2012)

Potential Problems With Severe Carbohydrate Restriction

VERY-LOW-CARB  EATING

First, let’s talk about ketogenic diets, which require reduction of digestible carbohydrates to 50 grams a day or less for most folks.  The iconic ketogenic diet is the induction phase of the Atkins diet, which restricts carbs to a max of 20 g daily.  Note that the average American eats 250 to 300 grams of carb daily.

Your body gets nearly all its energy either from fats, or from carbohydrates like glucose and glycogen. In people eating normally, 60% of their energy at rest comes from fats. In a ketogenic diet, the carbohydrate content of the diet is so low that the body has to break down even more of its fat to supply energy needed by most tissues. Fat breakdown generates ketone bodies in the bloodstream. Hence, “ketogenic diet.” Also called “very-low-carb diets,” ketogenic diets have been around for over a hundred years.

WHAT COULD GO WRONG EARLY ON?

Very-low-carb ketogenic diets have been associated with headaches, bad breath, easy bruising, nausea, fatigue, aching, muscle cramps, constipation, gout attacks, and dizziness, among other symptoms. “Induction flu” may occur around days two through five, consisting of achiness, easy fatigue, and low energy. It clears up after a few days.

Other effects that you might not even notice immediately (if ever) are low blood pressure, high uric acid in the blood, excessive loss of sodium and potassium in the urine, worsening of kidney disease, deficiency of calcium and vitamins A, B, C, and D, among other adverse effects.

A well-designed ketogenic diet should address all these potential issues.  My Ketogenic Mediterranean Diet is an example.  I followed it for for six months and blogged about it.  (The KMD is not a paleo diet.)

Athletic individuals who perform vigorous exercise should expect a deterioration in performance levels during the first three to four weeks of any ketogenic very-low-carb diet. The body needs that time to adjust to burning mostly fat for fuel rather than carbohydrate.

Competitive weight-lifters or other anaerobic athletes (e.g., sprinters) will be hampered by the low muscle glycogen stores that accompany ketogenic diets. They need more carbohydrates.

WHAT ABOUT THE LONG RUN?

Long-term effects of a very-low-carb or ketogenic diet in most people are unclear—they may have better or worse overall health—we just don’t know for sure yet. Perhaps some people gain a clear benefit, while others—with different metabolisms and genetic make-up—are worse off.

If the diet results in major weight loss that lasts, we may see longer lifespan, less type 2 diabetes, less cancer, less heart disease, less high blood pressure, and fewer of the other obesity-related medical conditions.

Ketogenic diets are generally higher in protein, total fat, saturated fat, and cholesterol than some other diets. Some authorities are concerned this may increase the risk of coronary heart disease and stroke; the latest evidence indicates otherwise.

Some authorities worry that ketogenic diets have the potential to cause kidney stones, osteoporosis (thin, brittle bones), gout, deficiency of vitamins and minerals, and may worsen existing kidney disease. Others disagree.

It’s clear that compliance with very-low-carb diets is difficult to maintain for six to 12 months. Many folks can’t do it for more than a couple weeks. Potential long-term effects, therefore, haven’t come into play for most users. When used for weight loss, regain of lost weight is a problem (but regain is a major issue with all weight-loss programs). I anticipate that the majority of non-diabetics who try a ketogenic diet will stay on it for only one to six months. After that, more carbohydrates can be added to gain the potential long-term benefits of additional fruits and vegetables.

Or not.

People with type 2 diabetes or prediabetes may be so pleased with the metabolic effects of a ketogenic diet that they’ll stay on it long-term.

Steve Parker, M.D.