Entries Tagged 'Weight Loss' ↓
February 17th, 2008 — Weight Loss
Weight gain is simply a matter of energy balance; if this energy balance is positive we gain weight. Americans are eating more both in the home and at fast food restaurants and this has been contributing to the positive energy balance portion of the ledger.
We are all witness to the “supersizing” phenomenon we see at restaurants. Food portion sizes have increased for all food categories except pizza from 1977 to 1996.1 Some examples include: salty snacks from 1 to 1.6 oz (22 calorie increase), soft drinks from 13.1 to 19.9 oz (12 calorie increase), hamburgers from 5.7 to 7 oz (23 calorie increase), French fries from 3.1 to 3.6 oz (16 calorie increase) and Mexican food from 6.3 to 8.0 oz (31 calorie increase). Remember every calorie counts; creating a positive energy balance of just 2.4 calories a day translates into an extra pound of weight per year.
February 5th, 2008 — Weight Loss
Body Mass Index (BMI) is used as an assessment of total body fat and is calculated as follows: BMI = weight (kg)/ height squared (m2)
Ideal is defined as BMI of 18.5-24.9 kg/ m2
Overweight is defined as BMI of 25 – 29.9 kg/m2
Obesity is defined as a BMI of > 30 kg/m2
Age and sex will influence BMI as a measure of total body fat:1
- As we age BMI will underestimate total body fat since we tend to lose lean tissue and gain body fat. For men and woman with a BMI of 23 body fat will increase by 1.0-1.1% and 0.7-1.0% respectively per decade.
- Woman will have significantly greater amounts of body fat than men at equivalent BMIs. A 20 year old woman and man with a BMI of 23 would have 26.0% and 13.3% body fat respectively.
1. How useful is body mass index for comparison of body fatness across age, sex and ethnic groups? Am J of Epidemiol 1996;143:228-39
January 21st, 2008 — Weight Loss
The National Weight Control Registry is the largest study ever of individuals who were highly successful at weight loss.1 To enroll in the Registry participants needed to have lost 30 lbs and have maintained the loss for a year or more. Registry participants actually did much better; on average 784 participants (629 women and 155 men) lost 66 lbs and maintained a minimum 30 lb weight loss for 5.5 years.
Some key strategies employed by these individuals include:
Consumed a low energy diet. – Women reported eating an average of 1306 calories day; men reported eating an average of 1685 calories day. Energy from fat was 24% in both women and men.2 The most popular methods to cut calories were to limit intake of certain types of classes of foods (88%), to limit portion sizes (44%), to count calories (44%) and to limit the amount of fat (31%).
Used a combination of diet and exercise – Registry participants were very active; they reported expending 2800 calories/week on physical activity. This amounts to 400 calories a day and is equivalent to one hour of brisk walking a day.
Employed self monitoring strategies – The majority of participants (75%) weighed themselves at least once a week while 38% weighed themselves everyday.
1. A descriptive study of individuals successful at long-term maintenance of substantial weight loss. Am J Clin Nutr 1997;66:239-46
2. Persons successful at long-term weight loss and maintenance continue to consume a low-energy, low-fat diet. J Am Diet Assoc 1998;98:408-13
December 27th, 2007 — Weight Loss, fitness
Physical fitness and your health
In a study by Steven Blair of the Cooper Institute increasing levels of physical fitness as measured by a treadmill test lowered the risk of mortality.1 Specifically least fit men had mortality rates 3.44 times higher than most fit men. For women the mortality rate was 4.65 times higher. Maximal fitness benefits with lower risks of mortality were attainable by individuals who engage regularly in moderate exercise (equivalent to a brisk walk of 30-60 minutes each day).
In 1995 the Centers for Disease Control and the American College of Sports Medicine advised American adults to accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week.2 Examples of moderate activities cited included brisk walking (3-4 mph), cycling less than 10 mph, swimming, moderate effort, conditioning exercise, racket sports, home care and general cleaning and mowing the lawn. Remember that these recommendations are to improve fitness and are not related to weight loss maintenance where greater levels of activity are required.
Fitness benefits for those overweight
It’s no surprise that obesity can be dangerous to your health. Studies from the Cooper Clinic demonstrate that overweight individuals have a 3 times higher cardiovascular death rate and double the overall mortality rate when compared to normal weight men.3
However when cardiovascular fitness was considered, fit obese individuals had lower mortality rates equivalent to fit lean men!4 Or put another way, unfit lean men had twice the risk of mortality of fit obese men. Clearly fitness offers equivalent protective health benefits for overweight individuals as compared with lean individuals.
1. Physical Fitness and All-Cause Mortality. JAMA 1989;262:2395-2401
2. Physical Activity and Public Health. A Recommendation From the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402-407
3. Relationship Between Low Cardiorespiratory Fitness and Mortality in Normal-Weight, Overweight, and Obese Men JAMA;282:1547-1553
4. Cardiorespiratory fitness, body composition, and all-cause and cardiovascular disease mortality in men. AM J Clin Nutr 1999;69:373-80
December 27th, 2007 — Weight Loss
Americans are becoming more overweight
Americans have become more overweight and obese.1 The prevalence of overweight (defined as a BMI 25 or higher) increased from 56% to 65% largely due to the rising prevalence of obesity (defined as a BMI of 30 or higher) which increased from 23% to 31%. These results are alarming and the health implications will be profound.
Obesity is as detrimental to your health as smoking
We have known that overweight and obesity are detrimental to our health but life expectancy results from the Framingham Heart Study are astonishing.2 Non-smoking obese adults (BMI >_ 30) at age 40 lived 6 to 7 years less than their normal weight counterparts. These decreases in life expectancy are similar to that seen with smoking. For non-smoking overweight individuals (BMI 25-29.9) lived about 3 years less than their normal weight counterparts.