Category Archives: Weight Loss

High Protein Diet May Prevent Weight Regain

Filet mignon and sautéed asparagus

Weight loss can change your metabolism in such a way that promotes regain of lost weight. For successful weight-losers with prediabetes, a higher protein diet could help with prevention of regain. How much higher protein? 25% versus the usual 15% of calories from fat.

This is important research since most people who lose fat weight gain it back, typically 6–12 months later.

For the boring details, keep reading.

ABSTRACT

Background

Weight loss has been associated with adaptations in energy expenditure. Identifying factors that counteract these adaptations are important for long-term weight loss and weight maintenance.

Objective

The aim of this study was to investigate whether increased protein/carbohydrate ratio would reduce adaptive thermogenesis (AT) and the expected positive energy balance (EB) during weight maintenance after weight loss in participants with prediabetes in the postobese state.

Methods

In 38 participants, the effects of 2 diets differing in protein/carbohydrate ratio on energy expenditure and respiratory quotient (RQ) were assessed during 48-h respiration chamber measurements ∼34 mo after weight loss. Participants consumed a high-protein (HP) diet (n = 20; 13 women/7 men; age: 64.0 ± 6.2 y; BMI: 28.9 ± 4.0 kg/m 2) with 25:45:30% or a moderate-protein (MP) diet (n = 18; 9 women/9 men; age: 65.1 ± 5.8 y; BMI: 29.0 ± 3.8 kg/m 2) with 15:55:30% of energy from protein:carbohydrate:fat. Predicted resting energy expenditure (REEp) was calculated based on fat-free mass and fat mass. AT was assessed by subtracting measured resting energy expenditure (REE) from REEp. The main outcomes included differences in components of energy expenditure, substrate oxidation, and AT between groups.

Results

EB (MP = 0.2 ± 0.9 MJ/d; HP = −0.5 ± 0.9 MJ/d) and RQ (MP = 0.84 ± 0.02; HP = 0.82 ± 0.02) were reduced and REE (MP: 7.3 ± 0.2 MJ/d compared with HP: 7.8 ± 0.2 MJ/d) was increased in the HP group compared with the MP group (P < 0.05). REE was not different from REEp in the HP group, whereas REE was lower than REEp in the MP group (P < 0.05). Furthermore, EB was positively related to AT (rs = 0.74; P < 0.001) and RQ (rs = 0.47; P < 0.01) in the whole group of participants.

Conclusions

In conclusion, an HP diet compared with an MP diet led to a negative EB and counteracted AT ∼34 mo after weight loss, in participants with prediabetes in the postobese state. These results indicate the relevance of compliance to an increased protein/carbohydrate ratio for long-term weight maintenance after weight loss. The trial was registered at clinicaltrials.gov as NCT01777893.

Source: High Compared with Moderate Protein Intake Reduces Adaptive Thermogenesis and Induces a Negative Energy Balance during Long-term Weight-Loss Maintenance in Participants with Prediabetes in the Postobese State: A PREVIEW Study | The Journal of Nutrition | Oxford Academic

Steve Parker, M.D.

PS: I didn’t read the whole study. I leave that to you.

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How’s Your New Years’ Weight Loss Resolution Working Out? If Not So Great, Let Me Help

That excess weight can shorten your life

If you’re down at least 4–5 pounds (2.5 kg) since Jan. 1, that’s great. Keep it up. But most folks did well for a couple weeks and started gaining the weight back. Don’t be too hard on yourself. Weight management is not a walk in the park. You probably weren’t adequately prepared for the challenge.

Longterm success requires careful forethought. That’s why I’ve written this eight-part series.

Questions beg for answers.  For example . . .

Which of the myriad weight-loss programs will I follow?  Can I design my own program?  Should I use a diet book?  Sign up for Nutri-System, Weight Watchers, or Jenny Craig?  Should I stop wasting my time dieting and go directly to bariatric surgery?  Can I simply cut back on sodas and chips?  What should I eat?  What should I not eat?  Do I need to start exercising?  What kind?  How much?  Do I need to join a gym?  What methods are proven to increase my odds of success?  How much weight should I lose?  Should I use weight-loss pills or supplements?  Which ones?  What’s the easiest, most effective way to lose weight?  Is there a program that doesn’t require willpower?  Now, what were those “top 10 super-power foods” that melt away the fat?  Am I ready to get serious and stick with it this time?

This series will answer many of these questions and get you teed up for success.  Teed up like a golfer ready to hit his first shot on hole #1 of an 18-hole course.  Take 10 minutes to read the following articles.  The time invested will pay dividends for years.

C’mon now. Let’s be realistic.

Part 1:  Motivation

Immediate, short-term motivation to lose weight may stem from an upcoming high school reunion, swimsuit season, or a wedding. You want to look your best. Maybe you want to attract a mate or keep one interested. Perhaps a boyfriend, co-worker, or relative said something mean about your weight. These motivators may work, but only temporarily. Basing a lifestyle change on them is like building on shifting sands. You need a firmer foundation for a lasting structure. Without a lifestyle change, you are unlikely to vanquish a chronic overweight problem.  Proper long-term motivation may grow from:

  • the discovery that you feel great and have more energy when you are lighter and eating sensibly
  • the sense of accomplishment from steady progress
  • the acknowledgment that you have free will and are responsible for your weight and many aspects    of your health
  • the inspiration from seeing others take charge of their lives successfully
  • the admission that you have some guilt and shame about being fat, and that you like yourself more when you’re not fat  [I’m not laying shame or guilt on you; many of us do it to ourselves.]
  • the awareness of overweight-related adverse health effects and their improvement with even modest weight loss.

Appropriate motivation will support the commitment and willpower that will be needed soon.

PS: I’m thinking of how Dave Ramsay, when he’s counseling people who have gotten way overhead in debt, tells them they have to get mad at the debt.  Then they can attack it.  Maybe you have to get mad at your fat.  It’s your enemy, dragging you down, trying to kill you.  Now attack it!

Part 2:  The Energy Balance Equation

An old joke from my medical school days asks, “How many psychiatrists does it take to change a light bulb?”  Only one, but the light bulb must want to change.

How many weight-loss programs does it take before you lose that weight for good?  Only one, but…

Where does the fat go when you lose weight dieting?  Metabolic reactions convert it to energy, water, and carbon dioxide, which weigh less than 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.  Even at rest, a kilogram of muscle is much more metabolically active than a kilogram of fat tissue.  So muscular lean people sitting quietly in a room are burning more calories than are fat people of the same weight sitting in the same room.

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.

If you want to lose excess weight and keep it off, you must learn the following equation:

The energy you eat,

          minus the energy you burn in metabolism and activity,

               determines your change in body fat.  [read more]

Cute mouse, but a slave to instincts.

Part 3:  Free Will

The only way to lose excess fat weight is to cut down on the calories you take in, increase your physical activity, or do both.

Oh, sure.  You could get a leg amputated, develop hyperthyroidism or out-of-control diabetes, or have liposuction or bariatric surgery.  But you get my drift.

Although the exercise portion of the energy balance equation is somewhat optional, you must reduce food intake to lose a significant amount of weight.  Once you reach your goal weight you will be able to return to nearly your current calorie consumption, and even higher consumption if you have increased your muscle mass and continue to be active.

Are you be able to reduce calorie intake and increase your physical activity temporarily? It comes down to whether we have free will.  Free will is the power, attributed especially to humans, of making free choices that are unconstrained by external circumstances or by an agency such as divine will.

Will is the mental faculty by which one chooses or decides upon a course of action; volition.

Willpower is the strength of will to carry out one’s decisions, wishes, or plans.

If we don’t have free will, you’re wasting time trying to lose weight through dieting; nothing will get your weight problem under control.  Even liposuction and weight-reduction stomach surgery will fail in time if you are fated to be fat.  The existence of free will is . . . [read more]

Part 4:  Starting New Habits

You already have a number of good habits that support your health and make your life more enjoyable, productive, and efficient.  For example, you brush your teeth and bathe regularly, put away clean clothes in particular spots, pay bills on time, get up and go to work every day, wear your seat belt, put your keys or purse in one place when you get home, balance your checkbook periodically.

At one point, these habits took much more effort than they do now.  But you decided they were the right thing to do, made them a priority, practiced them at first, made a conscious effort to perform them on schedule, and repeated them over time.  All this required discipline.  That’s how good habits become part of your lifestyle, part of you.  Over time, your habits require much less effort and hardly any thought.  You just do it.

Your decision to lose fat permanently means that you must establish some new habits, such as regular exercise and reasonable food restriction.  You’ve already demonstrated that you have self-discipline.  The application of that discipline to new behaviors will support your commitment and willpower.

Exercise isn’t very important for weight loss, but critical for preventing weight regain.

Part 5:  Supportive Social System

Success at any major endeavor is easier when you have a supportive social system.  And make no mistake: losing a significant amount of weight and keeping it off long-term is a major endeavor.

As an example of a supportive social system, consider childhood education.  A network of actors play supportive roles.  Parents provide transportation, school supplies, a home study area, help with homework, etc.  Siblings leave the child alone so he can do his homework, and older ones set an example.  Neighbors may participate in carpooling.  Taxpayers provide money for public schools.  Teachers do their part.  The school board oversees the curriculum, supervises teachers, and does long-range planning.

Success is more likely when all the actors work together for their common goal: education of the child.  Similarly, your starring role in a weight-loss program may win an Academy Award if you have a strong cast of supporting actors.  Your mate, friends, co-workers, and relatives may be helpers or hindrances.  It will help if they . . . [read more]

Part 6:  Weight Goals

Despite all the chatter about how to lose weight, few talk about how much should be lost.

"This can't be right!"

Down 4 pounds in 6 months. I’ll take it!

If you are overweight, deciding how much weight you should lose is not as simple as it seems at first blush.  I rarely have to tell a patient she’s overweight. She knows it and has an intuitive sense of whether it’s mild, moderate, or severe in degree.  She’s much less clear about how much weight she should lose.  If it’s any consolation, clinicians in the field aren’t always sure either.

Five weight standards have been in common usage over the last quarter-century . . . [read more]

Part 7:  Creative Visualization

How will your life be different after you make a commitment and have the willpower to lose weight permanently?

Odds are, you will be more physically active than you are now.  Exercise will be a habit, four to seven days per week.  Not necessarily vigorous exercise, perhaps just walking for 30 or 45 minutes.  It won’t be a chore.  It will be pleasant, if not fun.  The exercise will make you more energetic, help you sleep better, and improve your self-esteem.

After you achieve your goal weight, you’ll be able to cut back on exercise to three or four days per week, if you want.  If you enjoy eating as much as I do, you may want to keep very active physically so that you can eat more.  I must tell you that I rarely see anyone lose a major amount of weight and keep it off without . . . [read more]

Part 8:  Choosing A Program

I listed most of your weight-loss program options in the introductory comments to this series.  Now it’s time to make a choice.  And it’s not easy sorting through all the options.

Straight away, I must tell you that women over 300 pounds (136 kg) and men over 350 pounds (159 kg) rarely have permanent success with self-help methods such as diet books, meal replacement programs, diet pills or supplements, and meal-delivery systems.  People at those high weights who have tried and failed multiple different weight-loss methods should seriously consider bariatric surgery.

I respect your intelligence and desire to do your “due diligence” and weigh all your options: diet books, diet pills and supplements, bariatric surgery, meal replacement products (e.g., SlimFast), portion-control meal providers (e.g., NutriSystem), Weight Watchers, fad diets, no-diet diets, “just cutting back,” etc.  You have to make the choice; I can’t make it for you.  Here are some well-respected sources of advice to review before you choose . . . [read more]

Last modification date:  November 1, 2017

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What’s a Reasonable Rate of Weight Loss?

paleobetic diet, low-carb, diabetic diet, paleo diet

Java had to lose weight when he developed metabolic syndrome

P.D. Mangan posted a good article on the risks of rapid weight loss. I agree with him that a max of 1–2 pounds a week is a reasonable weight-loss goal, and that a bit more than that is OK in the first week but highly inadvisable for the long run. Most folks do well if they settle into one pound a week.

From P.D.:

Slower Metabolism

A slower metabolism is another side effect of losing weight too quickly; since your body’s metabolism is essentially determining how much fuel you are needing to burn every day based on your activities and food intake, dropping calories out of your diet can considerably lower your metabolism. While this might not seem like a big deal, it is! A lower metabolism essentially causes your body to burn fewer calories each day than it typically would, and some research even shows up to a 23% decrease in calories that are burned each day. This doesn’t always go away when you stop losing weight quickly, either, your metabolism might take a while to get back on track and burning appropriately, which could affect your health and weight for a long time.

Muscle Loss

Lastly, your body could end up losing muscle as part of your quick weight loss routine. Granted, eliminating calories from your diet will have you lose weight, yes, but aside from a lot of that weight being water, some of it can also be muscle. A recent study done with people on a 500 calorie diet versus a 1250 calorie diet showed significant results; by the end of the trial, the participants on the 500 calorie diet lost six times more muscle than those on the 1250 calorie diet – an astounding loss in muscle in just a five-week span of time.

Source: Risks of Losing Weight Too Quickly – Rogue Health and Fitness

Steve Parker, M.D.

low-carb mediterranean diet

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Cutting Back on Ultra-Processed Foods Should Help With Weight Loss

“How about some ultra-processed bread?”

Over the short term, those eating ultra-processed foods at 500 calories a day more than those eating unprocessed foods.

From Kevin D. Hall and associates at Cell Metabolism:

We investigated whether ultra-processed foods affect energy intake in 20 weight-stable adults, aged (mean ± SE) 31.2 ± 1.6 years and BMI = 27 ± 1.5 kg/m2. Subjects were admitted to the NIH Clinical Center and randomized to receive either ultra-processed or unprocessed diets for 2 weeks immediately followed by the alternate diet for 2 weeks. Meals were designed to be matched for presented calories, energy density, macronutrients, sugar, sodium, and fiber. Subjects were instructed to consume as much or as little as desired. Energy intake was greater during the ultra-processed diet (508 ± 106 kcal/day; p = 0.0001), with increased consumption of carbohydrate (280 ± 54 kcal/day; p < 0.0001) and fat (230 ± 53 kcal/day; p = 0.0004), but not protein (−2 ± 12 kcal/day; p = 0.85). Weight changes were highly correlated with energy intake (r = 0.8, p < 0.0001), with participants gaining 0.9 ± 0.3 kg (p = 0.009) during the ultra-processed diet and losing 0.9 ± 0.3 kg (p = 0.007) during the unprocessed diet. Limiting consumption of ultra-processed foods may be an effective strategy for obesity prevention and treatment.

Source: Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake: Cell Metabolism

Steve Parker, M.D.

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Are Drugs the Answer to Unhealthy Lifestyles?

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“This is much easier than exercising and losing 30 pounds!”

Fiona Godlee, editor-in-chief of the British Medical Journal, has a heretical short article at BMJ. I recommend you read the whole thing. It starts thusly:

More than half of adults aged over 45 will be labelled as hypertensive if new US guidelines are adopted, concludes a study in The BMJ this week (doi:10.1136/bmj.k2357). This equates to 70 million people in the US and 267 million people in China being eligible for antihypertensive drugs, a marked increase on already high rates of drug treatment for high blood pressure. Furthermore, the study calculates that 7.5 million people in the US and 55 million in China would be advised to start drug treatment, while 14 million in the US and 30 million in China would be advised to receive more intensive treatment. The evidence from trials indicates some benefit from drugs in terms of reduced risk of stroke and heart disease, but is mass medication really what we want?

Hypertension is just one of the many heads of the lifestyle disease hydra. Another is type 2 diabetes. Once thought to be irreversible and progressive, it is now known to be potentially reversible through weight loss. This is the cautious conclusion of the review by Nita Forouhi and colleagues (doi:10.1136/bmj.k2234), part of our series on the science and politics of nutrition (bmj.com/food-for-thought). Whether by calorie or carbohydrate restriction, weight loss has been shown to improve glycaemic control, blood pressure, and lipid profile and is the key to treatment and prevention of type 2 diabetes, they say.

She goes on to talk about fatty liver disease (NASH) and offers an alternative, of sorts, to pills. Good luck with that.

Source: Pills are not the answer to unhealthy lifestyles | The BMJ

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1/2 of American Adults Trying to Lose Weight

No wonder they’re not having much success:

“Exercise, eating less, consuming more fruits and vegetables and drinking more water were the most common strategies. The least common were skipping meals and cutting down on fatty foods.”

Source: Nearly Half of Americans Battling to Lose Weight: CDC Data – Bloomberg Quint

Drinking more water? Come on, America, get serious.

Steve Parker, M.D.

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Does High Protein Diet Help With Weight Loss?

Sous vide chicken and sautéed sugar snap peas. Chicken is a good source of high biologic value protein.

P.D. Mangan makes the case for high-protein diets for those hoping to shed pounds of fat:

In humans, data collected from 38 different trials of food consumption that used widely varying intakes of protein, from 8 to 54% of energy, showed: “Percent dietary protein was negatively associated with total energy intake (F = 6.9, P < 0.0001) irrespective of whether carbohydrate (F = 0, P = 0.7) or fat (F = 0, P = 0.5) were the diluents of protein. The analysis strongly supports a role for protein leverage in lean, overweight and obese humans.”

In obese humans, substitution of carbohydrate with protein leads to far greater weight loss, nearly twice as much.

In a human trial, decreasing the percentage of protein in food from 15% to 10% led to increased calorie intake of 12%. However, increasing the protein percentage from 15 to 25% did not affect calorie intake, which shows that humans may target a certain amount of protein, and eat no more or less when they get it.

There’s more at the link.

Source: Higher Protein for Greater Weight Loss – Rogue Health and Fitness

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From Vox: Why Do Diets Fail…or Succeed?

Julia Belluz has interesting article at Vox regarding low-fat and low-carb diet success over the course of 12 months. Her focus is on a few individuals who participated and were outliers.

As I read this, I was reminded that successful long-term weight management starts and ends in the kitchen. It also took me back to 2009, when I determined that low-carb diets were just as legitimate as low-fat.

I don’t recall the author mentioning the typical pattern with 12-month weight loss studies: most folks lose significant weight in the first few months, then at six months they start gaining it back. Cuz they go back to their old eating habits. Sure, diets don’t work………..if you don’t follow them.

From Ms. Belluz:

As a longtime health reporter, I see new diet studies just about every week, and I’ve noticed a few patterns emerge from the data. In even the most rigorous scientific experiments, people tend to lose little weight on average. All diets, whether they’re low in fat or carbs, perform about equally miserably on average in the long term.

But there’s always quite a bit of variability among participants in these studies. Just check out this chart from a fascinating February study called DIETFITS, which was published in JAMA by researchers at Stanford.

The randomized controlled trial involved 609 participants who were assigned to follow either a low-carb or a low-fat diet, centered on fresh and high-quality foods, for one year. The study was rigorous; enrollees were educated about food and nutrition at 22 group sessions. They were also closely monitored by researchers, counselors, and dietitians, who checked their weight, waist circumference, blood pressure, cholesterol, and other metabolic measures throughout the year.

Overall, dieters in both groups lost a similar amount of weight on average — 11 pounds in the low-fat group, 13 pounds in the low-carb group — suggesting different diets perform comparably. But as you can see in the chart, hidden within the averages were strong variations in individual responses. Some people lost more than 60 pounds, and others gained more than 20 during the year.

Read the whole thing. It’s not long.

Source: Why do dieters succeed or fail? The answers have little to do with food. – Vox

The DIETFITS Trial

Steve Parker, M.D.

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Have You Heard of the Milk Diet?

hiking, Arizona, Steve Parker MD,

Tom’s Thumb trail in Scottsdale, AZ

 

I vaguely recall a milk diet to treat stomach ulcers in the mid-20th century. Tagamet changed that!

I’ve been reading scientific articles on low-energy liquid diets for weight loss and diabetes remission, and ran across a reference to a milk diet. I found impressive results in a 16-week study.

This was a small randomized trial that enrolled 45 very fat folks — BMI 41-47, average weight 122 kg (268 lb), mostly women — and assigned them to one of three diets:

  1. Control: conventional balanced diet of normal foods providing about 800 calories/day and at least 36 grams of protein.
  2. Milk: “variable combination of full cream or semi-skimmed milk and unsweetened yoghurt,” about 800 calories/day. BTW, a cup (240 ml) of whole milk has 150 calories.
  3. Milk Plus: same as the milk diet plus “unlimited amount of a single food selected by the patient on each day of the week. Of these seven extra foods, three were a fruit or vegetable, two were a high protein food, and two were a “favourite” food. The seven foods were repeated on the same day of successive weeks.” (If you understand this, you’re smarter than me, which wouldn’t be unusual.) Average calories were 1,350/day.

The researchers figured these adults were eating about 2,500 calories/day at baseline. Diabetics were excluded.

Results

The Milk group lost the most weight. Eleven of the 14 participants completed the 16-week study, with an average weight loss of 11.2 kg (24.6 lb). Constipation was the only “serious” side effect reported. The authors admitted that deficiencies in some vitamins and iron might be a problem, but cited a similar but longer trial (24 weeks) that found no such deficiencies.

Eleven of the 17 in the Milk Plus group persevered for the whole 16 weeks. Average weight loss was 8.2 kg (18 lb).

Nine of the 14 in the Control Group were able to put up with it for the duration. Average weight loss was only 2.6 kg (5.7 lb). I suspect they had a bit of a compliance problem. When you weigh 268 lb, a 5.7 lb loss isn’t much.

“Analysis of compliance (not reported) showed that it was similar for the two milk diets but much lower for the conventional diet.”

Comments

The researchers opine that…

  • “Patients are more likely to respond to a simple diet which they have not tried before than to advice on conventional diets.”
  • Probably the best strategy is to rotate diets,…[to prevent compliance from falling].”

I wonder how well the Milk diet would work for someone who weighs 205 lb (93 kg) and just wants to lose 25 lb (11.4 kg).

I wonder how important are the exact proportions of “full cream or semi-skimmed milk and unsweetened yoghurt.”

I wonder if the Milk diet has ever been tested in overweight people with diabetes. The carbohydrate in milk shouldn’t be a problem since overall calories are so low. A cup of milk has 12 grams of carbohydrate.

As with all diets, weight regain will be a problem after the 16 weeks.

I’m skeptical about the nutritional adequacy of the Milk diet.

The Milk diet might be a good temporary option for someone who wants to lose more excess weight but has hit a weight-loss plateau in their current regimen.

The simplicity of the milk diet is very appealing to me.

Steve Parker, M.D.

Reference: Summerbell, C.D., et al. Randomised controlled trial of novel, simple, and well supervised weight reducing diets in outpatients. British Medical Journal, 317: 1487-1489. November 28, 1998.

Low-Carb Mediterranean Diet, front cover

 

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This May Be Why You’re Not Losing That Weight

Old-school preparation for exercise; stretching actually doesn’t do any good for the average person

You’ll see the term “diet resistant” in the scientific abstract below. It refers to folks who are on a reduced-calorie diet who aren’t losing the weight they should, base on total calorie consumption. Long story short, they’re eating much more than the think and exercising less than they think.

BACKGROUND AND METHODS

Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet — low total energy expenditure and underreporting of caloric intake — in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance.

RESULTS

Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic effects of food and exercise. Low energy expenditure was thus excluded as a mechanism of self-reported diet resistance. In contrast, the subjects in group 1 underreported their actual food intake by an average (±SD) of 47±16 percent and overreported their physical activity by 51±75 percent. Although the subjects in group 1 had no distinct psychopathologic characteristics, they perceived a genetic cause for their obesity, used thyroid medication at a high frequency, and described their eating behavior as relatively normal (all P<0.05 as compared with group 2).

CONCLUSIONS

The failure of some obese subjects to lose weight while eating a diet they report as low in calories is due to an energy intake substantially higher than reported and an overestimation of physical activity, not to an abnormality in thermogenesis. (N Engl J Med 1992; 327:1893–8.)

Source: Discrepancy between Self-Reported and Actual Caloric Intake and Exercise in Obese Subjects | NEJM

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