The general principle behind Bioelectrical Impedance (BIA): two conductors are held (on the hand held unit) and a small electrical current is sent through the upper body from one to the other.
The resistance between the conductors will provide a measure of body fat, since the resistance to electricity varies between adipose, muscular and skeletal tissue. Fat-free mass is more than 70% water and a good conductor of electrical current, while fat is a poor conductor. Based on the rate that electricity is conducted, a formula is used to estimate percentage of fat and lean body mass.
One problem with the formulas is they don’t seem to predict accurately for different ethnic groups. Another drawback to using the hand-held unit is they only measure upper body impedance; units that use hand and foot sensors give a better estimation since they measure impedance across the entire length of the body. Results from hand-held units may also vary due to individual differences in arm span/height ratios. Finally, results may be skewed by dehydration.
This study found the handheld units measured results that were reproducible but either over estimated or under estimated % fat mass in overweight women.
Despite these drawbacks, I still like the hand-held unit. It’s quick, easy, and gives you a result that in my opinion is in the ballpark for 70-80% of those I test. Since the results are highly reproducible, it also offers a very good measure of fat loss in subjects that do lose total body weight.
Research
bioelectrical impedance
In a six-year study of healthy men and women ages 20 to 78, weight gain was not related to weight cycling in men. Women weight cyclers, who gained about one pound a year, showed only a slight tendency to gain more weight than those whose weight did not cycle. -msnbc.com MY COMMENT: You don’t want to continue with yo-yo dieting if you can help it. Once you lose the weight, stick with regular exercise and monitor your weight weekly. Set a threshold that you do not want to exceed! If you lost weight with a very restrictive diet, you’ll probably regain some weight , but getting comfortable with healthier eating habits should keep you satisfied and leaner.
According to the article, risk of weight regain and risk factors including diabetes, high blood pressure, cancer and high cholesterol are NOT linked to history of weight cycling (losing and regaining). Correlations do exist between these risk factors and high body mass index.
Health Risks, Medical Conditions, Research
Health Risks, yo yo dieting
Think you’re going to lose fat faster by exercising?
Conclusions: Despite similar effect on fat losses, combining CR (calorie restriction) with exercise increased aerobic fitness in parallel with improved insulin sensitivity, LDL cholesterol, and diastolic BP. The results lend support for inclusion of an exercise component in weight loss programs to improve metabolic fitness. -Medicine & Science in Sports and Exercise
COMMENTS: This study split subjects into 3s- controls, a group that reduced calorie intake by 25%, and a combination group with 12.5% reduction in calories combined with a 12.5% increase in physical activity. The findings support previous research- you don’t accelerate fat loss by adding exercise when caloric deficits are the same, however the added benefits are significant. Other research has found that weight loss is more likely to be maintained in those who continue to exercise.
Research, Weight Loss Science
caloric restriction, Exercise, weight loss
Women who drank two or more diet sodas a day had a 30% drop in a measure of kidney function during the lengthy study follow-up -webmd.com
MY COMMENT: This is also startling- Kidney disease diagnoses have doubled each of the last two decades. 20 million Americans have some degree of chonic kidney disease. I suggest if you are a heavy diet soda drinker, consider switching to water or tea.
Medical Conditions, Research
diet soda, kidney disease
There are three different types of HFCS – one that is 55 percent fructose and 42 percent glucose (most commonly found in soft drinks), one that is 42 percent fructose and 58 percent glucose (usually used in food products), and one used for specialty applications that is 90 percent fructose and 10 percent glucose.
Pure fructose on its own – not HFCS – has been linked to weight gain in some animal studies, and this could be where some confusion arises, but Erickson and other industry members have repeatedly pointed out that the HFCS used in foods and beverages is not dissimilar in its makeup to sugar (sucrose), which contains 50 percent glucose and 50 percent fructose. Therefore, compared to sugar, the HFCS commonly found in foods is actually low-fructose, she said.
-Confectionary News
MY COMMENT: Very enlightening! The bottom line is, no matter what the percentages are, we still consume too.
Research, Weight Loss Science
high fructose corn syrup
Ever notice that when you’re really stressed, you tend to crave comfort foods that are high in fat or sugar? Researchers have found that specific hormones may play a role in this process. -everydayhealth.com
MY COMMENT: While this may be true, it doesn’t change the basic weight loss strategies I outline in Lose It For Ever.
Research, Weight Loss Science
stress, weight gain
Scientists found that when mice ate at unusual hours, they put on twice as much weight, despite exercising and eating as much as others.
The study, in the journal Obesity, is said to be the first to show directly that there is a “wrong” time to eat. bbcnews
MY COMMENT: Does this study translate to humans? You’ve been hearing this advice for years- stop eating after such and such a time, however this is the first study I’ve seen that supports the theory that eating late at night promotes weight gain. The mechanism is still not understood.
Research, Weight Loss Science
late night eating, weight gain
After adjusting for factors such as levels of physical activity, the researchers found that a higher intake of whole grains was associated with lower amounts of total body fat and abdominal fat. -everydayhealth.com
MY COMMENT: Interesting that subjects in this study (ave age 68 years) averaged only 18.6 grams of fiber daily.
Research, Weight Loss Science
fiber, weight loss, whole grains
…snack foods like popcorn and many popular breakfast cereals contain “surprisingly large” amounts of healthful antioxidant substances called “polyphenols.” -EurekAlert
MY COMMENT: Great news! More than just fiber in these whole grain products. Note that Raisin Bran had the highest levels (from the raisins).
Research
Reducing calorie intake slows aging and significantly delays the onset of age-related problems such as cardiovascular disease, diabetes, cancer, and brain atrophy in monkeys, a new study says.
According to the study, the incidence of cancerous tumors and cardiovascular disease in the monkeys on a restricted diet was half that seen in the animals that were allowed to eat freely. -webmd.com
MY COMMENT: I’d like to see what difference physical activity can make- will the monkeys be able to eat more and remain just as healthy? Also, good luck selling calorie restriction to the general public- we already know that most people would be better off if they ate less, and there is no sign that we are eating less.
Health Risks, Research
calorie restriction, health
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