Category Archives: Dietary Carbohydrate

PURE Study: High Carb Consumption Increases Risk of Death

How many innocent lives will be cut short by this tasty but silent killer?

Here’s the abstract of a new epidemiological study that investigated the relationships between diet, cardiovascular disease, and death rates. I don’t have the entire article. My sense is that the 18 countries studied are mostly non-Western:

Background

The relationship between macronutrients and cardiovascular disease and mortality is controversial. Most available data are from European and North American populations where nutrition excess is more likely, so their applicability to other populations is unclear.

Methods

The Prospective Urban Rural Epidemiology (PURE) study is a large, epidemiological cohort study of individuals aged 35–70 years (enrolled between Jan 1, 2003, and March 31, 2013) in 18 countries with a median follow-up of 7·4 years (IQR 5·3–9·3). Dietary intake of 135 335 individuals was recorded using validated food frequency questionnaires. The primary outcomes were total mortality and major cardiovascular events (fatal cardiovascular disease, non-fatal myocardial infarction, stroke, and heart failure). Secondary outcomes were all myocardial infarctions, stroke, cardiovascular disease mortality, and non-cardiovascular disease mortality. Participants were categorised into quintiles of nutrient intake (carbohydrate, fats, and protein) based on percentage of energy provided by nutrients. We assessed the associations between consumption of carbohydrate, total fat, and each type of fat with cardiovascular disease and total mortality. We calculated hazard ratios (HRs) using a multivariable Cox frailty model with random intercepts to account for centre clustering.

paleo diet, paleolithic diet, caveman diet

“Do you understand the words that are coming out of my mouth?”

Findings

During follow-up, we documented 5796 deaths and 4784 major cardiovascular disease events. Higher carbohydrate intake was associated with an increased risk of total mortality (highest [quintile 5] vs lowest quintile [quintile 1] category, HR 1·28 [95% CI 1·12–1·46], ptrend=0·0001) but not with the risk of cardiovascular disease or cardiovascular disease mortality. Intake of total fat and each type of fat was associated with lower risk of total mortality (quintile 5 vs quintile 1, total fat: HR 0·77 [95% CI 0·67–0·87], ptrend<0·0001; saturated fat, HR 0·86 [0·76–0·99], ptrend=0·0088; monounsaturated fat: HR 0·81 [0·71–0·92], ptrend<0·0001; and polyunsaturated fat: HR 0·80 [0·71–0·89], ptrend<0·0001). Higher saturated fat intake was associated with lower risk of stroke (quintile 5 vs quintile 1, HR 0·79 [95% CI 0·64–0·98], ptrend=0·0498). Total fat and saturated and unsaturated fats were not significantly associated with risk of myocardial infarction or cardiovascular disease mortality.

Interpretation

High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.

Source: Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study – The Lancet

Official Diabetic Diet Takes a Hit in the U.K.

DailyMail.com has a few of the details. A snippet:

More than 120,000 people signed up to a ‘low-carb’ diet plan launched by the forum diabetes.co.uk in a backlash against official advice.
More than 80,000 of those who ditched a low-fat high-carbohydrate diet found their blood glucose level drop after ten weeks.
By rejecting official guidelines and eating a diet high in protein and low in starchy food – along with ‘good saturated fats like olive and nuts – more than 80 per cent of the patients said they had lost weight.

An article at The Times says, “The results have led doctors to call for an overhaul of official dietary guidelines.”

Regular readers here won’t be surprised by these findings.

The road to this revolution is paved with scientific studies showing that dietary saturated fat has little or nothing to do with causing cardiovascular disease. I crossed that Rubicon in 2009.

If you want the benefits of low-carb eating, check out my free Paleobetic Diet. The book is even better.

Steve Parker, M.D.

PS: If you think carbs are bad, my books have zero digestible carbs. Unless you’re a termite.

Paleobetic Diet-FrontCover_300dpi_RGB_5.5x8.5

Increase in consumption of refined carbohydrates and sugar may have led to the health decline of the Greenland Eskimos 

Not much edible carbohydrate this time of year...

Not much edible carbohydrate this time of year…

From Dr. James Dr. DiNicolantonio:

“In conclusion, an increase in the intake of refined carbohydrate and sugar paralleled the rise in atherosclerotic disease in the Greenland Eskimos. While the total carbohydrate intake of the Greenland Eskimos was just 2–8% of total calories in 1855, this increased to around 40% of calories by 1955.5 The Greenland Eskimos studied by Bang and Dyerberg in the 1970s no longer consumed a traditional healthy Eskimo diet. Indeed, the intake of refined sugar in the Greenland Eskimos increased by almost 30-fold from 1855 (6 g/person/day or around 1½ teaspoonful of sugar) to the 1970s (164–175 g or around 40–44 teaspoonful of sugar). Moreover, the intake of refined carbohydrate increased 5–7-fold from 1855 (18 g/day from bread) to the 1970s (84–134 g/day from bread, biscuits and rye flour).

In summary, the intake of refined carbohydrate and sugar by the Greenland Eskimos increased in parallel to the rise in atherosclerotic disease. Considering that a similar event occurred in the USA and that the overconsumption of refined sugar is a principal driver of type 2 diabetes, hypertension, and coronary heart disease, this most likely explains the health decline of the Greenland Eskimos.”

Source: Increase in the intake of refined carbohydrates and sugar may have led to the health decline of the Greenland Eskimos — DiNicolantonio 3 (2) — Open Heart

Is Insulin Making You Hungry All the Time?

So easy to over-eat!

So easy to over-eat! Is it the insulin release?

No, insulin probably isn’t the cause of constant hunger, according to Dr. Stephan Guyenet. Dr. G gives 11 points of evidence in support of his conclusion. Read them for yourself. Here are a few:

  • multiple brain-based mechanisms (including non-insulin hormones and neurotransmitters) probably have more influence on hunger than do the pure effect of insulin
  • weight loss reduces insulin levels, yet it gets harder to lose excess weight the more you lose
  • at least one clinical study (in 1996) in young healthy people found that foods with higher insulin responses were linked to greater satiety, not greater hunger
  • billions of people around the world eat high-carb diets yet remain thin

An oft-cited explanation for the success of low-carbohydrate diets involves insulin, specifically the lower insulin levels and reduced insulin resistance seen in low-carb dieters. They often report less trouble with hunger than other dieters.

Here’s the theory. When we eat carbohydrates, the pancreas releases insulin into the bloodstream to keep blood sugar levels from rising too high as we digest the carbohydrates. Insulin drives the bloodstream sugar (glucose) into cells to be used as energy or stored as fat or glycogen. High doses of refined sugars and starches over-stimulate the production of insulin, so blood sugar falls too much, over-shootinging the mark, leading to hypoglycemia, an undeniably strong appetite stimulant. So you go back for more carbohydrate to relieve the hunger induced by low blood sugar. That leads to overeating and weight gain.

Read Dr. Guyenet’s post for reasons why he thinks this explanation of constant or recurring bothersome hunger is wrong or too simplistic. I agree with him.

The insulin-hypoglycemia-hunger theory may indeed be at play in a few folks. Twenty years ago, it was popular to call this “reactive hypoglycemia.” For unclear reasons, I don’t see it that often now. It was always hard to document that hypoglycemia unless it appeared on a glucose tolerance test.

Regardless of the underlying explanation, low-carb diets undoubtedly are very effective in many folks. And low-carbing is what I always recommend to my patients with carbohydrate intolerance: diabetics and prediabetics.

Steve Parker, M.D.

front cover

front cover

One Man’s N=1 Experiment Comparing Lower- Versus Moderate-Carb Diet For His Diabetes

Use the search box to find the recipe for this low-carb avocado chicken soup

Use the search box to find the recipe for this low-carb avocado chicken soup

Read his amazingly detailed post at Diatribe. Adam, who has type 1 diabetes, figured out during his college days that eating no more that 30 grams of carbs at a time was “a complete gamechanger” for improving his blood sugars. He experimented on himself to see if there was a difference between his usual lower-carb diet (146 grams/day) versus 313 grams/day.

A quote:

To my utter surprise, both diets resulted in the same average glucose and estimated A1c. But there were major tradeoffs:

The higher-carb, whole-grain diet caused four times as much hypoglycemia, an extra 72 minutes per day spent high, and required 34% more insulin. (A less healthy high-carb diet would have been far worse.)

Doubling my daily carbs also added much more effort and produced far more feelings of exhaustion and diabetes failure. It was not fun at all, and the added roller coaster, or glycemic variation, from all the extra carbs made it more dangerous.

See more at: http://diatribe.org/low-carb-vs-high-carb-my-surprising-24-day-diabetes-diet-battle#sthash.pZOgCWVl.dpuf

I think the lower-carb approach is healthier over the long run. Check with your own healthcare provider before making any drastic change in your diabetic diet.

Steve Parker, M.D.

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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