Category Archives: Weight Loss

Do Low-Carb Diets Cause Premature 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, 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 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

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Which Macronutrient Helps the Most With Appetite Control and Weight Management?

You can make a good case for protein. Julianne Taylor has the sciencey details in a fine post at her blog. She talks about insulin, glycogen, digestion, glycemic index, and the benefits of vegetable and fruit carbohydrates over grains.

Read the whole enchilada.

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Ketogenic Diet Overview

"Waiter, I didn't order sushi!"

“Waiter, I didn’t order sushi!”

Below is my contribution to Low-Carbing Among Friends—Vol. 4, which is an excellent source of low-carb recipes. Get the whole series so you’ll never suffer from diet boredom!

*  *  *

We’re starting to see a resurgence of interest in ketogenic diets for weight loss and management, at least in the United States. Also called “very-low-carb diets,” ketogenic diets have been around for over a hundred years. A few writers in the vanguard recently are Jimmy Moore, Dr. Peter Attia, and Dr. Georgia Ede. Before them, Dr. Robert Atkins was a modern pioneer with his famous Atkins Diet and its Induction Phase.

What is a Ketogenic Diet?

There are many different programs but they tend to share certain characteristics. They restrict digestible carbohydrate consumption to 50 or fewer grams a day, sometimes under 20 grams. This totally eliminates or drastically reduces some foods, such as grains, beans, starchy vegetables (corn, potatoes, peas, etc), milk, and sugar. Nor can you have products made from these, such as bread, cookies, pies, cakes, potato and corn chips, and candy. You eat meat, eggs, fish, chicken, certain cheeses, nuts, low-carb vegetables (e.g., salad greens, broccoli, green beans, cauliflower), and oils. Total calorie consumption is not restricted; you count carb grams rather than calories. This is a radical change in eating for most people.

Raspberries and blackberries are low-carb fruits

Raspberries and blackberries are low-carb fruits

You’re may be wondering what “ketogenic” means. First, understand that 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.” Some of the recent writers are using the phrase “nutritional ketosis” to summarize this metabolic state.

Ketogenic Versus Traditional Calorie-Restricted Dieting

Are there advantages to ketogenic diets for weight loss and management? Numerous recent studies have demonstrated superior weight-loss results with very-low-carb diets as compared to traditional calorie-restricted diets. Weight loss is often faster and more consistently in the range of one or two pounds (0.5 to 0.9 kg) a week. Very-low-carb dieters have less trouble with hunger. If you do get hungry, there’s always something you can eat. From a practical, day-to-day viewpoint, these diets can be easier to follow, with a bit less regimentation than calorie-restricted plans.

Ketogenic diets typically lower blood sugar levels, which is important for anyone with diabetes, prediabetes, and metabolic syndrome. We see higher levels of HDL cholesterol (the good kind), lower triglyceride levels, and a shift in LDL cholesterol to the “large fluffy” kind, all of which may reduce the risk of heart disease. Getting even further into the science weeds, very-low-carb diets reduce insulin levels in people who often have elevated levels (hyperinsulinemia), which may help reduce chronic diseases like type 2 diabetes, high blood pressure, some cancers, and coronary heart disease.  Clearly, ketogenic diets work well for a significant portion of the overweight population, but not for everybody.

Sounds great so far! So why aren’t very-low-carb diets used more often? Many dieters can’t live with the restrictions. Your body may rebel against the switch from a carbohydrate-based energy metabolism to one based on fats. Most of us live in a society or subculture in which carbohydrates are everywhere and they’re cheap; temptation is never-ending.

What Could Go Wrong on a Ketogenic Diet?

Very-low-carb ketogenic diets have been associated with headaches, bad breath, easy bruising, nausea, fatigue, aching, muscle cramps, constipation, and dizziness, among other symptoms.

“Induction flu” may occur around days two through five, consisting of achiness, easy fatigue, and low energy. Atkins dieters came up with the term. It usually clears up after a few days. Some people think of induction flu as a withdrawal syndrome from sugar or refined carbohydrate. My conception is that it’s simply an adjustment period for your body to switch from a carbohydrate-based energy system to one based on fat. Your body cells need time to rev up certain enzymes systems while mothballing other enzymes. To prevent or minimize induction flu, Drs. Stephen Phinney, Jeff Volek, and Eric Westman routinely recommend eating 1/2  tsp (2.5 ml) of table salt daily.

Very-low-carb ketogenic diets may have the potential to cause osteoporosis (thin, brittle bones), kidney stones, low blood pressure, constipation, gout, 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. From a practical viewpoint, these are rarely seen, and many experts say they don’t occur in a well-designed ketogenic diet eaten by an essentially healthy person. I favor ketogenic diets designed by physicians or dietitians. In view of these potential adverse effects, however, it’s a good idea to run your ketogenic diet of choice by your personal physician before you get started. This is especially important if you have diabetes, chronic kidney or liver disease, or a history of gout, low blood pressure, or kidney stones.

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

Competitive weightlifters or other anaerobic athletes (e.g., sprinters) may be hampered by the low muscle glycogen stores that accompany ketogenic diets. They may need more carbohydrates, perhaps 150 grams a day.

What’s Next After Losing Weight on a Ketogenic Diet?

Caprese salad: mozzarella cheese, tomatoes, basil, extra virgin olive oil

Caprese salad: mozzarella cheese, tomatoes, basil, extra virgin olive oil

A majority of folks eventually increase their carbohydrate consumption above 50 grams a day, which usually takes them out of nutritional ketosis. If they return to the typical 200-300 grams a day that most people eat, they’ll probably gain the lost weight back. Many have found, however, that they can go up to 70-100 grams and maintain at a happy weight. A well-designed program should give careful instructions on the transition out of ketosis and avoidance of regain.

To see a ketogenic diet I designed for my patients, click here.

Steve Parker, M.D.

PS: Another ketogenic diet blogger I’ve been following lately is ItsTheWooo (The Scribble Pad), a nurse who lost major weight on the diet. And don’t overlook Amber and Z. Wilcox-O’Hearn at The Ketogenic Diet for Health.

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QOTD: James Fell on Cooking and Weight Loss

If you want to lose weight you need to cook. Period.

James Fell

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Ketogenic Diet Works for Children

ketogenic diet, children

Is there a trampoline out of view?

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 monitor 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.

Steve Parker, M.D.

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Chaz Bono Loses 65 Pounds in Six Months Eating Low-Carb

Examiner.com has the details:

“I really avoid grains and starches, so meats and vegetables and fruits are my diet,” he tweeted. “I make them all different ways to keep it interesting. What’s worked for me is no sugar, no grains, no dairy except goat cheese, no white starches, portion control, and high intensity workouts.”

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“ItsTheWooo” Explains Reluctance to Try Very-Low-Carb Eating For Weight Management

Click for details. ITW, BTW, is a nurse. A snippet:

At work, a few days ago, I was sitting at the station alongside a new nurse; she’s very young (about my age when I first started using a ketogenic diet for my obesity) and she is also very very overweight. In addition to being a young female (thus common sense that she prefers to be thin), observing her eating behavior made it patently obvious this poor girl has been trying for years to correct her obesity.  She always refuses food if offered to her, and when she does bring food, she rarely eats it, and it’s always healthy food like salads.

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One More Study Shows Low-Carb Beats Low-Fat Diet for Weight Loss

low-carb diet, low-carb fruits, Steve Parker MD

Low-carb isn’t meat-only: You can eat these low-carb fruits

A low-carb diet was superior to a traditional low-fat weight loss diet, and without adverse effects on markers of systemic inflammation, according to a report at ScienceDaily. Some medical professionals are still hesitant to accept the validity of low-carb dieting, fearing that relatively high fat and protein content may promote inflammation, leading to atherosclerosis.  The study at hand should be reassuring in that regard.

Some quotes from ScienceDaily:

The researchers measured the participants’ blood levels for three common markers of inflammation — C-reactive protein, interleukin 6 and tumor necrosis factor-alpha — at the beginning and end of the study. They also measured body weight, body mass index (BMI) and total body and belly fat. At the start, both groups were similar in the various measures, including elevated levels of inflammation markers.

The participants on the low-carb diet lost more weight, on average, than those on the low-fat diet — 28 pounds versus 18 pounds [over the six month trial.

“In both groups, there was a significant drop in the levels of all three measures of inflammation,” says [Kerry] Stewart, indicating that a diet higher in fat and protein doesn’t interfere with the ability to lower inflammation, as long as you are losing weight.

Despite reading several online articles on this study, I can’t determine which low-carb diet was used, nor the level of carbohydrate restriction. Both diet groups exercised three times a week. I expect full details to be published in a scientific journal within a couple years. The research was done at Johns Hopkins University and was not funded by Atkins Nutritionals. U.S. taxpayers funded it.

If you’re looking for a low-carb diet, consider the Low-Carb Mediterranean Diet. Carb restriction starts at under 30 grams a day, but allows for increases over time as long as you’re making weight-loss progress. The typical American eats 250 to 300 grams of carbohydrate daily.

Read the rest at ScienceDaily.

Steve Parker, M.D.

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Once Again, Low-Carbohydrate Ketogenic Diet Beats Low-Calorie For Overweight Diabetes

Kuwait City and Towers

Kuwait City and Towers

A low-carbohydrate ketogenic diet is safe, effective, and superior to a low-calorie diet in type 2 diabetics, according to a report last year in Nutrition.

Kuwaiti researchers gave 102 adult overweight diabetic men and women their choice of diet: 78 chose ketogenic, 24 went low-calorie.  Average age was 37, average weight 211 lb (96 kg).  The study lasted six months.  The ketogenic diet was very much Atkins-style, starting out at 20 grams of carbohydrate daily.  Once good weight-loss progress was made, and if carb cravings were an issue, dieters could increase their carbs in small increments weekly.

This is all they said about the low-calorie diet: “Participants in the low-calorie diet group were given appropriate guidelines and a sample low-calorie diet menu of 2200 calories is presented in Table 1″ (it’s typical and reasonable).

What Did They Find?

The low-carb ketogenic dieters lost 12% of body weight, compared to 7% lost by the low-calorie dieters.  Furthermore, the ketogenic dieters showed significant lowering of total cholesterol, LDL cholesterol (bad cholesterol), and triglycerides.  HDL cholesterol (good cholesterol) rose.  The low-calorie dieters seem to have had a significant drop in LDL cholesterol, but no changes in the other lipids.

Fasting blood sugar levels dropped significantly in both groups, but more in the ketogenic dieters.  Both groups started with fasting blood sugars around 162 mg/dl (9 mmol/l) and fell to 108 mg/dl (6 mmol/l) in the ketogenic group and to 126 mg/dl (7 mmol/l) in the low-calorie group.

Glycosylated hemoglobin (hemoglobin A1c) levels fell in both groups, more so in the ketogenic dieters.  The drop was statistically significant in the ketogenic group, but the authors were unclear about that in the low-calorie dieters.  It appears hemoglobin A1c fell from 7.8% to 6.3% with the ketogenic diet (the units given for glycosylated hemoglobin were stated as mg/dl).  In the low-calorie dieters, hemoglobin A1c fell from 8.2 to 7.7%.

What’s Odd About This Study?

The title of the research report indicates a study of diabetics, but only about 25% of study participants had diabetes (total subjects = 363).  (The figures I share above are for the diabetics only.)

Glycosylated hemoglobin, a test of overall diabetes control, is reported in Fig. 1 in terms of mg/dl.  That’s nearly always reported as a percentage, not mg/dl.  Misprint?

None of the participants dropped out of the study.  That’s incredible, almost unbelievable.

The low-calorie diet was poorly described.  Were 140-lb women and 250-lb men all put on the same calorie count?

Food diaries were kept, but the authors report nothing about compliance and actual food intake.

Clearly, some of these diabetics were on insulin and other diabetic drugs.  The authors note necessary reductions in drug dosages for the ketogenic group but don’t say much about the other dieters.  They imply that the drug reductions in the low-calorie group were minimal or nonexistent.

Grand Mosque of Kuwait

Grand Mosque of Kuwait

So What?

Calorie-restricted diets are effective in overweight type 2 diabetics, but ketogenic diets are even better.

The effectiveness and safety of ketogenic diets for overweight type 2 diabetics has been demonstrated in multiple other populations, so this study is not surprising.  We’ve seen these lipid improvements before, too.

The favorable lipid changes on low-carb ketogenic diets would tend to reduce future heart and vascular disease.

I know little about Kuwaiti culture and genetics.  Their contributions to the results here, as compared with other populations, is unclear to me.  Type 2 diabetes is spreading quickly through the Persian Gulf, so this research may have wide applicability there.

Steve Parker, M.D.

Reference:  Hussain, Talib, et al.  Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes.  Nutrition, 2012; 28(10): 1016-21. doi: 10.1016/j.nut.2012.01.016

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Mediterranean and Low-Carb Diets Beat Low-Fat for Weight Loss Over Six Years

Israeli flag

Remember Shai et al’s 2008 DIRECT study that compared weight loss over two years on either a low-carb, low-fat, or Mediterranean diet?  I reviewed it at length in 2008.

The same Isreali researchers now report the results of an additional four years of follow-up.  Do you know of any other weight loss study over that length of time?  I don’t.

Of the 322 original study participants, 259 were available for follow-up for an additional four years.  Of these, 67% told researchers they had continued their originally assigned diet.

Over six years, the weight loss was as follows:

  • 0.6 kg (about a pound) in the low-fat group
  • 1.7 kg (almost 4 pounds) in the low-carb cohort
  • 3.1 kg (almost 7 pounds) in the Mediterranean group

The difference between the low-carb and Mediterranean groups was not statistically significant.

Almost all the original study participants (86%) were men, so it’s debatable whether these results apply to women.  I bet they do.  I assume most of the participants were Israeli, so you can also debate whether results apply to other nationalities or ethnicities.

Bottom Line

For long-term weight management, Mediterranean and low-carb diets appear to be more effective than traditional low-fat, calorie-restricted dieting.

Beth Mazur at her Weight Maven blog has some worthwhile comments about the study.

Incidentally, my Advanced Mediterranean Diet (2nd Edition) book features both a traditional Mediterranean diet and the world’s first low-carb Mediterranean diet.

Steve Parker, M.D.

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