BMI Unreliable

Two recent studies have questioned the use of the Body Mass Index (BMI). A study published in the American Journal of Clinical Nutrition has found that the BMI based risk categories overestimate the risks associated with excess weight in people aged over 75. A second study Published in The Lancet found that cardiac patients classified as Overweight (25-29.9) using the BMI had lower risk of death than patients classified as Normal weight (20-24.9) or Underweight (<20).

The BMI, which is calculated as weight (kg) divided by the square of height (m), is an easily measured indicator of obesity and is used by most expert bodies such as the National Institutes of Health and the World Health Organisation.

The studies revealed that those with a low BMI were at the highest risk of death. According to the studies’ authors, an explanation for the lack of positive association with BMI and mortality at older ages is that BMI is a poor measure of abdominal fat, the key determinant of metabolic abnormalities that contribute to cardiovascular risk. The BMI does not differentiate between fat and fat-free mass so as older people lose muscle with age their BMI drops making them appear healthier. There can be substantial differences in percentage of fat and lean body mass between individuals whose BMIs are the same.

The better outcomes in overweight and mildly obese people may be because these people have a greater lean ‘muscle’ mass than normal weight and severely obese people. Lean muscle mass is important because it is metabolically active tissue, meaning that it burns energy, so the more muscle mass you have the higher your metabolism and the more fat you burn. Greater muscle mass may also indicate increased physical activity, which independently contributes to reduced coronary artery disease.

Waist circumference, which has been proposed as an alternate measure of obesity, was found to have no association with mortality. “A limitation of waist circumference alone as a measure is that it takes no account of body composition, whereas waist hip ratio is a measure of body shape and to some extent lower trunk adiposity [abdominal fat]“, said the one of the studies’ authors.

The first study found the Waist Hip Ratio (WHR) to be a better indicator of mortality risk in older people. The authors concluded that WHR should be used for people over the age of 75 because of its positive association with risk of death and that particular attention should be paid to the problem of muscle loss in old age.

Parents Influence Obesity

The amount and quality of time parents spend with their children has a direct effect on children’s rates of obesity, according to a new study from Texas A&M University.

The five year study found that the more time a mother spends with her child, the less likely that child is to be obese, however fathers were found to be a bad influence on their child’s obesity. “For a long time we thought that parents ought to influence what their kids eat, but we were not sure how that worked.” Lead researcher Professor Alex McIntosh said.

Because so many families are headed by two working parents, the focus of the research was to look at how the parents’ work-related stress, flexibility and general work conditions influenced the children’s nutrition, McIntosh said.

The study found that the fathers of 9 to 11-year-olds’ spend an average of 80 minutes per day with their children, while mothers’ average time spent with their children is 125 minutes. Children ages 13-15 included in the study saw their fathers an average of 95 minutes per day, while mothers of this age group spent an average 87 minutes per day with their children.

Income levels for the mother and father were also evaluated, examining the effects on a child’s nutritional intake. Professor George Davis from the department of agricultural economics at Texas A&M, said as parents’ income goes up, their children’s body mass index also increases. His advice to parents: “You’re not at work 24 hours a day. For mothers: For the time you do have, spend some with your kids. For fathers: Dads are not toxic, but people who teach nutrition education may be talking to the wrong audience. Men in general tend to have more muscles and less fat than women do, and consequently can eat more food without gaining weight. That means they may not be paying as much attention to nutrition as women do. “We may need to teach fathers about nutrition,” McIntosh said.

 

Website Reducing Waistlines

Sydney, Australia, August 16, 2006 – A free website is helping people who want to lose weight and be more healthy. Mikibo, which launched last December, has thousands of members in 37 countries across 6 continents, and its members are seeing results. Since launch Mikibo’s members have lost more than 10,000 pounds of body weight.

Mikibo’s key features are food and exercise diaries, exercise plans and support groups. By tracking their eating and exercise habits, members are able to see what they are doing right and where they could improve. Mikibo founder and exercise physiologist Dr Toby Heap says that Mikibo is an educational experience for its members. “By keeping a food diary members quickly learn which foods are causing problems, and which foods are not. Most people get a shock when they record their food intake for the first time” says Heap.

The World Health Organisation has stated that obesity has reached epidemic proportions globally. There are more than a billion overweight people in the world and at least 300 million are obese.[1]

Being overweight increases the likelihood of death and illness from conditions such as: type two diabetes, sleep apnoea, osteoarthritis, psychological problems and reproductive problems.[2]

While genetic and environmental factors play a role, the main cause of obesity is an imbalance between energy intake (food and drink) and energy expenditure (exercise and metabolism). This energy imbalance is caused by an increased consumption of more energy-dense, nutrient-poor foods and reduced physical activity.[3]

The shift towards less physically demanding work, increased use of cars and public transport and more passive leisure activities means that average energy requirements are falling. If our energy requirements are lower this means that we have to increase the proportion of fresh fruit and vegetables in our diet if we want to continue getting the same level of micronutrients (vitamins and minerals). Mikibo helps members to see if they are getting the recommended intake of micronutrients, such as calcium and iron, and warns members if they are having too much saturated fat or if their diet is high in cholesterol or sodium.

Mikibo was started by Dr Toby Heap who has a PhD in exercise physiology from the University of Sydney. As an athlete who was keeping food and exercise diaries he saw an opportunity to use technology to assist people to improve their health and fitness. “Keeping a food diary is a very repetitive process that involves a lot of adding up daily totals. It struck me that this was a perfect application for the Internet” says Heap.

Mikibo aims to empower members to lead more healthy lives. “We are providing our members with the tools and information they need so that they can improve their health and fitness through a sensible approach to nutrition and exercise” says Heap.

Unlike other weight loss and fitness services Mikibo is free to join. To become a member of Mikibo people can visit www.mikibo.com.

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[1] World Health Organization, www.who.int

[2] Australian Institute of Health and Welfare, www.aihm.gov.au

[3] World Health Organization, www.who.int

What are the World’s best runs?

We are compiling the Mikibo Top Runs 2006 list and would like your help. Please nominate your top runs in the comments to this article or in the Mikibo Running Group. Once nominations are complete we will hold a vote on Mikibo to determine the top 10 runs for 2006.

To join Mikibo visit www.mikibo.com

New Gym and Triathlon Groups

We have added two new groups to Mikibo. By popular demand we added a gym users group where you can discuss your favorite gyms, classes, instructors, equipment etc. We have also added a triathlon group for those of your who like the sport. If you’re a member if Mikibo then you should check out these new groups. If you are not yet a member then you can join for free at www.mikibo.com

Rationalizing obesity

A new study has found that more than four out of five Americans characterized their eating habits as healthy. This is despite the fact that 65% of American adults are overweight and over 30% are obese. The study conducted by Thomson Medstat involved a telephone survey of 12,000 American adults as part of the 2006 PULSE survey, America’s largest ongoing, privately sponsored consumer health survey. The findings of the survey suggest that for most people obesity is the result of occasional indulgence in a number of risky behaviors.

In addition to the specific eating and lifestyle habit questions, respondents were asked for their heights and weights. Results were then categorized by respondents’ body mass index (BMI) to determine trends among underweight, normal weight, overweight, obese and morbidly obese people.

When respondents were asked how often they consumed fast foods, ‘upsized’ their fast foods and ate unhealthy snacks there were small differences between normal weight and overweight people. However, over half of the respondents said they did not exercise for 20 minutes more than two times per week.

One result that was very clear was the relationship between respondents who reported that they had diabetes and BMI. Five percent of the normal weight respondents reported having diabetes. This rose to 9% for overweight respondents, 19% for obese respondents and a staggering 34% for morbidly obese respondents.

The conclusion is that while very few people from any of the BMI categories consistently ate super sized fast foods, snacked recklessly or even characterized their eating habits as poor, several high risk behaviors have combined to become part of the average American’s weekly routine. Through a combination of occasional fast foods, moderate snacking, not quite enough exercise and the belief that these habits are ’somewhat healthy’, Americans are rationalizing themselves into ever-expanding waistlines and diabetes.

Mikibo training diary update

You can now add detailed notes about your training sessions in the training diary. Click on the name of any exercise that you have added to your diary and you will be able to record your training details. This should be particularly useful for recording sets, reps and load in strength training and for recording interval training breakdowns in endurance training.

Join Mikibo at www.mikibo.com