Tag Archives: Weight Loss

Ketogenic Mediterranean Diet Now in Book Form

A number of my patients and blog readers have asked for a more comprehensive presentation of the Ketogenic Mediterranean Diet. The KMD, as you may be aware, is the basis for the Low-Carb Mediterranean Diet.  Both of them are in Conquer Diabetes and Prediabetes: The Low-Carb Mediterranean Diet.

Odd cover, huh?

The new book is geared for folks who don’t have diabetes, but want to lose weight with a very-low-carb diet.  It’s called KMD: Ketogenic Mediterranean Diet.  Readers of Conquer Diabetes and Prediabetes will get nothing out of the new book: they’ve seen it all before.  Here’s the book description from Amazon.com:

Dr. Steve Parker presents the world’s first low-carbohydrate Mediterranean diet. Nutrition experts for years have recommended the healthy Mediterranean diet. It’s linked to longer life span and reduced rates of heart attack, stroke, cancer, diabetes, and dementia. Dr. Parker (M.D.) has modified the Mediterranean diet to help you lose excess weight while retaining most of the healthy foods in the traditional Mediterranean diet. What’s the secret? Cut back on the fattening carbohydrates such as concentrated sugars and refined starches.

You’ll discover how to manage your weight without exercise, without hunger, without restricting calories, while eating fish, meat, chicken, vegetables, fruits, wine, olive oil, nuts, and cheese.

The book includes advice on how to avoid weight regain, instruction on exercise, a week of meal plans, special recipes, a general index, a recipe index, and scientific references. All measurements are given in both U.S. customary and metric units. This low-carbohydrate Mediterranean diet is included also in Dr. Parker’s Advanced Mediterranean Diet (2nd edition) and Conquer Diabetes and Prediabetes. Are you finally ready to lose weight while eating abundantly and without counting calories?

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KMD: Ketogenic Mediterranean Diet is available for purchase at Amazon.com (Kindle edition here, also) or Barnes and Noble (Nook version here).  The ebook version is available in multiple formats at Smashwords

Steve Parker, M.D.

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Filed under ketogenic diet, Mediterranean Diet, My KMD Experience, Shameless Self-Promotion, Weight Loss

Rapper Fat Joe Loses 100 lb on Low-Carb Diet

Rapper Fat Joe is in a YouTube video talking about his 100-lb (45 kg) weight loss by eating low-carb.  He’s not doctor, but he knows a lot about preventing diabetes and heart disease.  He’s livin’ it.

Steve Parker, M.D.

h/t Tom Naughton

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Severe Carb Restriction in Type 2 Diabetes

U.K. researchers found major metabolic improvements in obese type 2 diabetics following a very low-carbohydrate diet, compared to a low-fat portion-controlled diet.  The latter is a standard recommendation in the U.S. for overweight type 2 diabetics.
 
This study is an oldie (2005) but a goodie.
 
Methodology
 
The investigators randomly assigned 102 poorly controlled diabetics to follow one of the two diets for three months.  Participants had average weights of 224 pounds (102 kg),  body mass index 36, age 58, hemoglobin A1c’s of 9%.  Half of them were men.  About 40% of the diabetics in both groups were on unspecified oral diabetic drugs; 20% were on insulin and 40% were using a combination of the two.  Sulfonylurea was mentioned, but not metformin. 
 
Participants were randomly assigned to either a low-fat portion-controlled weight-loss diet or a low-carbohydrate diet.  The goal with the low-carb diet was “up to 70 g of carbohydrate per day,” including at least a half a pint of milk and one piece of fruit.  (Is a UK pint the same as in the US?).  Increased physical activity was recommended to both groups. 
 
Only 79 of the 102 participants made it through the three-month diet intervention.  Drop-out rate was the same for both groups.
 
What Did They Find?
 
(Differences are statistically significant unless otherwise noted.)
Weight loss for the low-carb group was 3.55 kg (7.8 lb) compared to only 0.92 kg (2 lb) for the low-fat cohort.
 
The total/HDL cholesterol ratio improved for the low-carb group (absolute decrease of 0.48 versus 0.10). 
 
Hemoglobin A1c and systolic blood pressure tended to decrease more for the low-carb group, but did not reach statistical significance.  For instance, HgbA1c dropped 0.55% (in absolute terms) for the low-carb group, and 0.23% for the low-fat group.  Lower HgbA1c indicates improved blood sugar control.
 
Caloric intake was not different between the groups (about 1350 cals/day by diet recall method).
 
The low-carb group reduced carbs to 109 g/day compared to 168 g in the  low-fat cohort.
 
The low-carb group consumed 33% of energy as carbs compared to 45% for the low-fat group.
 
The low-carb group consumed 40% of energy as fat compared to 33% in the low-fat cohort.
 
Protein intake was 26% of energy for the low-carbers compared to 21% for the low-fatters.
 
Absolute saturated fatty acid intake was higher for the low-carbers, but still considered moderate.
 
Insulin dose was reduced in about 85% of the insulin users in the low-carb group but in only 22% of the low-fat group.  Oral diabetic pill use was unchanged in both groups.
 
Comments
 
This is a classic research report that I cited in Conquer Diabetes and Prediabetes: The Low-Carb Mediterranean Diet.
 
The improved total/HDL cholesterol ratio in the low-carbers may reduce risk of heart and vascular disease.  These investigators didn’t look at LDL particle size.  Other studies have found that low-carb eating tends to shift LDL cholesterol (bad stuff) from small dense particles to light fluffy particles, which are thought to be less harmful to arteries.
 
The authors considered reduction of carbs to 109 grams a day to be “severe.”  That compares to 275 grams a day eating by the typical U.S. citizen.  I agree that a reduction of carbs by two-thirds is major restriction.  Dr. Richard Bernstein and I consider severe restriction to be 20–30 grams, or perhaps up to 50 g.
 
I suspect the improved metabolic numbers in the low-carbers would have been even more dramatic if they had reduced carbs well below 100 grams a day.  The Ketogenic Mediterranean Diet reduces digestible carbs to 20–30 grams daily.  Many diabetics start losing control of their blood sugars when daily carbs exceed 60–80 grams.
 
Low-carb diets often yield better weight loss than low-fat calorie-restricted diets, as was seen here.  This is often attributed to lower calorie consumption on the low-carb diets.  These investigators didn’t see that here.
 
Low-carb diets are often criticized as being hard to stick with.  The low-carbers here didn’t have any more drop-outs than the low-fat group.  Granted, it was only a three-month study.
 
Based on what we know today, the reduced need for insulin in these patients was entirely predictable. 
 
The authors had some concern about the higher relative saturated fatty acid consumption in the low-carbers.  In 2011, we know that’s not much, if any, cause for concern.
 
 
 
 
Reference: Daly, M.E., et al.  Short-term effects of severe dietary carbohydrate-restriction advice in Type 2 diabetes—a randomized controlled trialDiabetic Medicine, 23 (2006): 15-20.  doi: 10.1111/j.1464-5491.2005.01760.x

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Does Loss of Excess Weight Improve Longevity?

High WHR

Intentional weight loss didn’t have any effect either way on risk of death, according to recent research out of Baltimore.  Surprising, huh?

Obesity tends to shorten lifespan, mostly due to higher rates of cancer and cardiovascular disease like heart attacks and strokes.  Doctors and dietitians all day long recommend loss of excess weight, figuring it will reduce the risk of obesity-related death and disease.  Many of them are unaware that’s not necessarily the case.  It’s called the “obesity paradox“: some types of overweight and obese patients actually seem to do better (e.g., live longer) if they’re above the so-called healthy body mass index of 18.5 to 24.9.  For instance: those with heart failure, coronary artery disease, and advanced kidney disease.

It’s never really been clear whether the average obese person (body mass index over 30) improves his longevity by losing some excess weight.  That’s what the study at hand is about.

Methodology

Baltimore-based investigators followed the health status of 585 overweight or obese older adults over the course of 12 years.  Half of them were randomized to an intentional weight loss intervention.  All of them had a high blood pressure diagnosis.  Average age was 66.  Average body mass index was 31.  Details of the weight-loss intervention are unclear, but it was probably along the lines of “eat less, exercise more.”

What Did They Find?

The weight-loss group lost and maintained an average of 4.4 kg (9.7 lb) over the 12 years of the study.  This is about 5% of initial body weight, the minimal amount thought to be helpful for improvement in weight-related medical and metabolic problems.  Most of the weight loss was over the first three years.

The men assigned to the weight-loss program had about half the risk of dying over the course of the study, compared to the men not assigned to weight loss.  The authors don’t seem to put much stock in it, however, stating that “…no significant difference overall was found in all-cause mortality between older overweight and obese adults who were randomly assigned to an intentional weight-loss intervention and those who were not.” 

Comments

With regards to the men losing weight, we’re only talking about 100-150 test subjects, a relatively small number.  So I understand why the researchers didn’t make a big deal of the lower mortality: it may not be reproducible.

This same research group did a similar study of 318 arthritis patients and intentional weight loss, finding a 50% lower death rate over eight years.

The authors reviewed many similar studies done by other teams, noting increased death rates from weight loss in some studies, and lesser death rates in others. 

When the studies are all over the place like this, it usually means there’s no strong association either way.  Nearly all the pertinent studies were done on relatively healthy, middle-aged and older folks.  The most reliable thing you can say about the issue is that loss of excess fat weight doesn’t increase your odds of premature death

 Remember that patients with coronary heart disease, congestive heart failure, or advanced kidney disease tend to live longer if they’re overweight or at least mildly obese.  It’s the obesity paradox.  Will they live longer or die earlier if they go on a weight-loss program?  We don’t know.

We do know that intentional weight loss helps:

  • prevent type 2 diabetes
  • maintain reasonable blood pressures (avoiding high blood pressure)
  • improves lower limb functional ability

Maybe that’s enough.

Steve Parker, M.D.

Reference: Shea, M.K., et al.  The effect of intentional weight loss on all-cause mortality in older adults: results of a randomized controlled weight-loss trial.  American Journal of Clinical Nutrition, 94 (2011): 839-846.

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Low-Carb Diet Reduces Weight AND Increases Adiponectin

Compared to a low-fat diet, a very-low-carb diet yielded better fat loss and improved adiponectin levels, according to researchers at the University of Cincinnati.  Read on to find out why this matters.

Adiponectin is a hormone-like protein secreted by fat cells. But the fatter you are, the less adiponectin you have in your bloodstream.  This hormone has several effects:

    • it’s anti-inflammatory
    • high levels of one form of it (a high molecular weight oligomer) are linked to lower rates of diabetes
    • low circulating levels are associatedwith athersclerosis (hardening of the arteries), high blood pressure, and impaired function of cells lining our arteries
    • it sensitizes the liver and muscles to insulin, which helps keep blood sugars under control

    In summary, it’s a good thing to have around.  Low levels are linked to illnesses.  Overweight and obesity tend to lower your levels of adiponectin.  If you’re overweight and have low levels of adiponectin, you should be healthier if you can raise your levels.  How do you do that?  Lose weight.

U. of Cincinnati investigators wanted to know if a very-low-carb diet would increase adiponectin levels better than a common low-fat weight loss diet.  They randomized 81 obese women to follow either a low-fat diet (American Heart Association Step 1) or a very-low-carbohydrate diet based on the Atkins diet.  Women followed the diets for either four or six months.

Findings

Both groups lost weight, but the very-low-carb group lost more: 9.1 kg loss for very-low-carb vs 4.97  for the low-fat group.

The very-low-carb group lost more body fat: 5.45 kg vs 2.62 kg.  (Fat loss was determined by DEXA scan.)

Adiponectin increased in the VLC group but not the LF group.

Discussion

We can’t tell from this article if adiponectin results would be the same in men.  The authors didn’t mention.

ResearchBlogging.orgIn fairness, the authors cite another similar study that found equal degrees of weight loss and adiponectin increase in both low-fat and low-carb groups.  It was a year-long intervention and average weight loss was 13.5% for both groups, a greater degree of weight loss than in the study at hand, in which the very-low-carb group lost 10% of body weight and the low-fat group lost 5.4%.  So you can probably increase your leptin with a low-fat diet if you lose enough excess weight.

Would the Ketogenic Mediterranean Diet work just as well as the very-low carb diet used in this study?  I suspect so, but don’t have the $500,000 it would take to do the research.  Care to donate?

Steve Parker, M.D.

Reference:
Summer, S., Brehm, B., Benoit, S., & D’Alessio, D. (2011). Adiponectin Changes in Relation to the Macronutrient Composition of a Weight-Loss Diet Obesity DOI: 10.1038/oby.2011.60

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Filed under Carbohydrate, Overweight and Obesity, Weight Regain

Spanish Ketogenic Mediterranean Diet Cures Metabolic Syndrome

The very-low-carb Spanish Ketogenic Mediterranean Diet cures metabolic syndrome, according to investigators at the University of Córdoba in Spain. 

The metabolic syndrome is a collection of clinical factors that are linked to high risk of developing type 2 diabetes and heart disease.  Individual components of the syndrome include elevated blood sugar, high trigylcerides, low HDL cholesterol, high blood pressure,  and abdominal fat accumulation.

Spanish researchers put 26 people with metabolic syndrome on the Spanish Ketogenic Mediterranean Diet for twelve weeks and monitored what happened.  At baseline, average age was 41 and average body mass index was 36.6.  Investigators didn’t say how many diabetics or prediabetics were included.  No participant was taking medication.

What’s the Spanish Ketogenic Mediterranean Diet?

Calories are unlimited, but dieters are encouraged to keep carbohydrate  consumption under 30 grams day.  They eat fish, lean meat, eggs, chicken, cheese, green vegetables and salad, at least 30 ml (2 tbsp) daily of virgin olive oil,  and 200-400 ml of red wine daily ( a cup or 8 fluid ounces  equals 240 ml).  On at least four days of the week, the primary protein food is fish.  On those four days, you don’t eat meat, chicken, eggs, or cheese.  On up to three days a week, you could eat non-fish protein foods but no fish on those days. 

How’s this different from my Ketogenic Mediterranean Diet?  The major differences are that mine includes one ounce (28 g) of nuts daily, less fish overall, and you can mix fish and non-fish protein foods every day.

Regular exercisers were excluded from participation, and my sense is that exercise during the diet trial was discouraged. 

What Were the Results?

Metabolic syndrome resolved in all participants.

Three of the original 26 participants were dropped from analysis because they weren’t compliant with the diet.  Another one was lost to follow-up.  Final analysis was based on the 22 who completed the study.

Eight of the 22 participants had adverse effects.  These were considered slight and mostly appeared and  disappeared during the first week.  Effects included weakness, headache, constipation, “sickness”, diarrhea, and insomnia. 

Average weight dropped from 106 kg (233 lb) to 92 kg (202 lb).

Body mass index fell from 36.6 to 32.

Average fasting blood sugar fell from 119 mg/dl (6.6 mmol/l) to 92 mg/dl (5.1 mmol/l).

Triglycerides fell from 225 mg/dl to 110 mg/dl.

Average systolic blood pressure fell from 142 mmHg to 124.

Average diastolic blood pressure fell from 89 to 76.

So What?

A majority of people labeled with metabolic sydrome continue in metabolic sydrome for years.  That’s because they don’t do anything effective to counteract it.  These researchers show that it can be cured in 12 weeks, at least temporarily, with the Spanish Ketogenic Mediterranean Diet.

ResearchBlogging.orgVery-low-carb diets are especially good at lowering trigylcerides, lowering blood sugar, and raising HDL cholesterol.  Overweight dieters tend to lose more weight, and more quickly, than on other diets.  Very-low-carb diets, therefore, should be particularly effective as an approach to metabolic syndrome.  It’s quite possible that other very-low-carb diets, such as Atkins Induction Phase, would have performed just as well as the Spanish Ketogenic Mediterranean Diet.  In fact, most effective reduced-calorie weight-loss diets would tend to improve metabolic syndrome, even curing some cases, regardless of carb content

Most physicians recommend that people with metabolic syndrome either start or intensify an exercise program.  The program at hand worked without exercise.  I recommend regular exercise for postponing death and other reasons.

Will the dieters of this study still be cured of metabolic syndrome a year later?  Unlikely.  Most will go back to their old ways of eating, regaining the weight, and moving their blood sugars, triglycerides, and HDL cholesterols in the wrong direction.

Steve Parker, M.D.

Reference: Pérez-Guisado J, & Muñoz-Serrano A (2011). A Pilot Study of the Spanish Ketogenic Mediterranean Diet: An Effective Therapy for the Metabolic Syndrome. Journal of medicinal food PMID: 21612461

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Filed under ketogenic diet, Mediterranean Diet, Overweight and Obesity

Book Review: The Dukan Diet

With a suspicion that the Dukan Diet may be the next diet fad in the U.S., I read The Dukan Diet: 2 Steps to Lose the Weight, 2 Steps to Keep It Off Forever by Pierre Dukan (2011, first American edition).  On Amazon.com’s rating system, I give it two stars.

♦   ♦   ♦

Think of Dukan as a Low-Fat Atkins Diet.

The Dukan Diet is apparently very popular in Europe.  It’s comprised of four phases. The Attack Phase, also called “Pure Protein,” lasts usually two to seven days.  Eat all you want from the protein-rich food list, mostly skinless chicken, low-fat meat, fish, and nonfat dairy.  No carbs at all except for the dairy.  The Cruise Phase is next: Alternate Pure Protein days with proteins and non-starchy vegetables until you’re at your goal weight.  Eat all you want from the low-carb veggie list.  Consolidation Phase lasts five days for every pound lost.  Eat more variety but limited quantities: two slices of whole grain bread, one portion each of fruit and cheese daily, one or two servings of starchy carbs (e.g., legumes, flour, cereals), plus two “celebration meals” a week, carefully defined.  Proteins and low-carb veggies are still unlimited.  Finally, the Permanent Stabilization Phase is lifelong and similar to Consolidation Phase, but requires one Pure Protein day per week, such as Thursdays.  Also, take no stairs or elevators.  All phases include prescribed servings of oat bran.

During the active weight loss phases, this diet is low-fat, low-carb, and high-protein. You don’t have to count carb grams, fat grams, or calories.  Presumably, Dr. Dukan has done all that for you, although he never shares the average calories consumed nor the macronutrient breakdown (i.e., what percentage of calories are derived from protein, fat, or carbs). The latter two phases are still very low-fat but allow a bit more carbs.

I liked this book more than I expected.  It’s obvious the author has copious experience with dieters, especially women.  The writing is clear.  He’s a serious, earnest man, not a charlatan.  Although some will criticize the book’s repetitiveness, it’s a proven educational technique.  For weight management, Dr. Dukan and I agree that 1) weighing daily is good, 2) abstinence from sugar rarely eliminates the longing for sweets, 3) artificial no-calorie sweeteners are OK, 4) the 4-7 pound weight loss in Attack Phase is mostly water, not fat, 5) discipline and willpower are important, 6) after losing weight, you’ll regain it if you ever return to your old ways, and 7) a realistic weight goal is essential. 

Dr. Dukan recommends at least 20-30 minutes a day of walking.  He provides little information on resistance training, although increasing evidence supports it as a great weight control measure.  I wish he’d mentioned high intensity interval training (HIIT).

The book contains numerous recipes, including a week of menus for the Attack Phase.  Disappointingly, none of the recipes include nutritional analysis.

You’ll find an index.  It doesn’t list glycogen.  Insulin, a primary fat-storage hormone, is mentioned on only one page, one sentence.

This is one fat-phobic diet.  In Dr. Dukan’s view, “fat in food is the overweight person’s most deadly enemy.”  All fat consumption contributes to fatness, and animal fats “pose a potential threat to the heart.”  It seems Dr. Dukan never got the memo that total and saturated fat content of foods have little, if anything, to do with heart or other cardiovascular disease. While criticizing Dr. Atkins’ diet for demonizing carbohydrates, Dr. Dukan demonizes fats.  Yet Dr. Dukan does all he can to banish both carbohydrates and fats from his weight loss phases. 

Dr. Dukan makes several erroneous statements, including 1) all food is made up of only three nutrients, 2) all alcoholic beverages are high in carbohydrates, 3) all shellfish are carbohydrate-free, 4) he implies that when dieting or fasting, we convert much of our fat into glucose, 5) there are no indispensable fats, 6) fat is bad for the cardiovascular system, 7) vinegar is the only food containing sour taste, 8) fruit is the only natural food containing rapid-assimilation sugars, 9) “Anyone who loses and regains weight several times becomes immune to dieting,” 10) weight loss releases into the bloodstream artery-toxic fat and cholesterol, 11) many overweight folks are unusually good at extracting calories from food, 12) some people can gain weight even while they sleep, 13) exercise is vitally important for losing weight, and 14) the Atkins diet raises triglycerides and cholesterol levels dangerously.

Will the diet work?  I’m sure many have lost weight with it and kept it off.  It does, after all, limit two of the major causes of excess weight: sugars and refined starches. 

In considering rating this book two or three stars, I asked myself if I’d recommend it to one of my patients looking to lose weight.  Initially I had concern that the diet may be deficient in essential fatty acids since it’s so fat-phobic.  “Essential” means necessary for life and health.  Then I figured that the body’s own fat stores would provide adequate essential fatty acids, at least in the first two phases.  The later stages, I’m not so sure.  Carefully choosing specific foods would eliminate the risk, but how many people know how to do that?  Separate from that potential drawback, there are other diets that are better for the non-diabetic population, such as The New Atkins Diet for a New You, Protein Power, the Ketogenic Mediterranean Diet (free on the Internet), and The New Sonoma Diet.  You’ll have no risk of fatty acid deficiency with those.

For people with diabetes or prediabetes, I like Atkins Diabetes Revolution, Dr. Bernstein’s Diabetes Solution, and, of course, Conquer Diabetes and Prediabetes: The Low-Carb Mediterranean Diet.

 If you limit carbs, there’s just no need for fat-phobia.

Steve Parker, M.D.

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Pilot Study: Paleo Diet Is More Satiating Than Mediterranean-Style

Swedish researchers reported recently that a Paleolithic diet was more satiating than a Mediterranean-style diet, when compared on a calorie-for-calorie basis in heart patients.  Both groups of study subjects reported equal degrees of satiety, but the paleo dieters ended up eating 24% fewer calories over the 12-week study.

The main differences in the diets were that the paleo dieters had much lower consumption of cereals (grains) and dairy products, and more fruit and nuts.  The paleos derived 40% of total calories from carbohydrate compared to 52% among the Mediterraneans.

Even though it wasn’t a weight-loss study, both groups lost weight.  The paleo dieters lost a bit more than the Mediterraneans: 5 kg vs 3.8 kg (11 lb vs 8.4 lb).  That’s fantastic weight loss for people not even trying.  Average starting weight of these 29 ischemic heart patients was 93 kg (205 lb).  Each intervention group had only 13 or 14 patients (I’ll let you figure out what happened to to the other two patients).

I blogged about this study population before.  Participants supposedly had diabetes or prediabetes, although certainly very mild cases (average hemoglobin A1c of 4.7% and none were taking diabetic drugs)

As I slogged through the research report, I had to keep reminding myself that this is a very small, pilot study.  So I’ll not bore you with all the details.

Bottom Line

This study suggests that the paleo diet may be particularly helpful for weight loss in heart patients.  No one knows how results would compare a year or two after starting the diet.  The typical weight-loss pattern is to start gaining the weight back at six months, with return to baseline at one or two years out.

Greek investigators found a link between the Mediterranean diet and better clinical outcomes in known ischemic heart disease patients.  On the other hand, researchers at the Heart Institute of Spokane found the Mediterranean diet equivalent to a low-fat diet in heart patients, again in terms of clinical outcomes.  U.S. investigators in 2007 found a positive link between the Mediterranean diet and lower rates of death from cardiovascular disease and cancer

We don’t yet have these kinds of studies looking at the potential benefits of the paleo diet.  I’m talking about hard clinical endpoints such as heart attacks, heart failure, cardiac deaths, and overall deaths.  The paleo diet definitely shows some promise.

I also note the Swedish investigators didn’t point out that weight loss in overweight heart patients may be detrimental.  This is the “obesity paradox,” called “reverse epidemiology” at Wikipedia.  That’s a whole ‘nother can o’ worms.

Keep your eye on the paleo diet.

Steve Parker, M.D.

Reference: Jonsson, Tommy, et al.  A paleolithic diet is more satiating per calorie than a mediterranean-like diet in individuals with ischemic heart diseaseNutrition and Metabolism, 2010, 7:85.

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Exercise, Part 2: The Fountain of Youth and Other Metabolic Effects

Part 1 of the Exercise series focused on how regular physical activity prevented or postponed death. Onward now to other benefits.

Waist Management

Where does the fat go when you lose weight dieting? Chemical reactions convert it to energy, water, and carbon dioxide, which weigh less than the fat. Most of your energy supply is used to fuel basic life-maintaining physiologic processes at rest, referred to as resting or basal metabolism. Basal metabolic rate (BMR) is expressed as calories per kilogram of body weight per hour.

The major determinants of BMR are age, sex, and the body’s relative proportions of muscle and fat. Heredity plays a lesser role. Energy not used for basal metabolism is either stored as fat or converted by the muscles to physical activity. Most of us use about 70 percent of our energy supply for basal metabolism and 30 percent for physical activity. Those who exercise regularly and vigorously may expend 40–60 percent of their calorie intake doing physical activity. Excess energy not used in resting metabolism or physical activity is stored as fat.

Insulin, remember, is the main hormone converting that excess energy into fat; and carbohydrates are the major cause of insulin release by the pancreas.

To some extent, overweight and obesity result from an imbalance between energy intake (food) and expenditure (exercise and basal metabolism). Excessive carbohydrate consumption in particular drives the imbalance towards overweight, via insulin’s fat-storing properties.

In terms of losing weight, the most important metabolic effect of exercise is that it turns fat into weightless energy. We see that weekly on TV’s “Biggest Loser” show; participants exercise a huge amount. Please be aware that conditions set up for the show are totally unrealistic for the vast majority of people.

Physical activity alone as a weight-loss method isn’t very effective. But there are several other reasons to recommend exercise to those wishing to lose weight. Exercise counteracts the decrease in basal metabolic rate seen with calorie-restricted diets. In some folks, exercise temporarily reduces appetite (but others note the opposite effect). While caloric restriction during dieting can diminish your sense of energy and vitality, exercise typically does the opposite. Many dieters, especially those on low-calorie poorly designed diets, lose lean tissue (such as muscle and water) in addition to fat. This isn’t desirable over the long run. Exercise counteracts the tendency to lose muscle mass while nevertheless modestly facilitating fat loss.

How much does exercise contribute to most successful weight-loss efforts? Only about 10 percent on average. The other 90 percent is from food restriction.

Fountain of Youth

Regular exercise is a demonstrable “fountain of youth.” Peak aerobic power (or fitness) naturally diminishes by 50 percent between young adulthood and age 65. In other words, as age advances even a light physical task becomes fatiguing if it is sustained over time. By the age of 75 or 80, many of us depend on others for help with the ordinary tasks of daily living, such as housecleaning and grocery shopping. Regular exercise increases fitness (aerobic power) by 15–20 percent in middle-aged and older men and women, the equivalent of a 10–20 year reduction in biological age! This prolongation of self-sufficiency improves quality of life.

Heart Health

Exercise helps control multiple cardiac (heart attack) risk factors: obesity, high cholesterol, elevated blood pressure, high triglycerides, and diabetes. Regular aerobic activity tends to lower LDL cholesterol, the “bad cholesterol.” Jogging 10 or 12 miles per week, or the equivalent amount of other exercise, increases HDL cholesterol (“good cholesterol”) substantially. Exercise increases heart muscle efficiency and blood flow to the heart. For the person who has already had a heart attack, regular physical activity decreases the incidence of fatal recurrence by 20–30 percent and adds an extra two or three years of life, on average.

Effect on Diabetes

Eighty-five percent of type 2 diabetics are overweight or obese. It’s not just a random association. Obesity contributes heavily to most cases of type 2 diabetes, particularly in those predisposed by heredity. Insulin is the key that allows bloodstream sugar (glucose) into cells for utilization as energy, thus keeping blood sugar from reaching dangerously high levels. Overweight bodies produce plenty of insulin, often more than average. The problem in overweight diabetics is that the cells are no longer sensitive to insulin’s effect. Weight loss and exercise independently return insulin sensitivity towards normal. Many diabetics can improve their condition through sensible exercise and weight management.

Miscellaneous Benefits

In case you need more reasons to start or keep exercising, consider the following additional benefits: 1) enhanced immune function, 2) stronger bones, 3) preservation and improvement of flexibility, 4) lower blood pressure by 8–10 points, 5) diminished premenstrual bloating, breast tenderness, and mood changes, 6) reduced incidence of dementia, 7) less trouble with constipation, 7) better ability to handle stress, 8) less trouble with insomnia, 9) improved self-esteem, 10) enhanced sense of well-being, with less anxiety and depression, 11) higher perceived level of energy, and 12) prevention of weight regain.

People who lose fat weight but regain it cite lack of exercise as one explanation. One scientific study by S. Kayman and associates looked at people who dropped 20 percent or more of their total weight, and the role of exercise in maintaining that loss. Two years after the initial weight loss, 90 percent of the successful loss-maintainers reported exercising regularly. Of those who regained their weight, only 34 percent were exercising.

 Part 3 of this series gets into specific exercise recommendations.

Steve Parker, M.D.

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ADA Weight-Loss Guidelines for 2011

Earlier this month the American Diabetes Association published its Standards of Care in Diabetes—2011

The ADA recommends weight loss for all overweight diabetics.

For weight loss, either low-carbohydrate [under 130 g/day], low-fat calorie-restricted, or Mediterranean diets may be effective in the short-term (up to two years).  For those on low-carb diets, monitor lipids, kidney function, and protein consumption, and adjust diabetic drugs as needed…The optimal macronutrient composition of weight loss diets has not been established. [Macronutients are carbohydrates, proteins, and fats.]

Until three years ago, the ADA recommended against carbohydrate-restricted diets for overweight diabetics.  In January, 2008, their position statement noted that such diets may be effective for up to one year.  My recollection is that their 2010 guidelines also said “up to one year” and didn’t mention the  Mediterranean diet. 

Progress!

Looks like the timing of my Low-Carb Mediterranean Diet is good.

Steve Parker, M.D.

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Filed under Carbohydrate, Mediterranean Diet, Weight Loss