Healthier You Facts: OBESITY
Obesity is defined as excess adipose tissue. Dietary fat is calorie-dense , 9 calories in a gram vs 4 calories in a gram of protein or carbohydrates. If taken in excess of the body’s needs and not balanced with physical activity can result in excess body fat storage .
For adults, overweight and obesity ranges are determined by using weight and height to calculate a number called the "body mass index" (BMI). BMI is used because it correlates with amount of body fat. However, BMI does not directly measure body fat. As a result, some people, such as athletes, may have a BMI that identifies them as overweight even though they do not have excess body fat.
- An adult who has a BMI between 23 and 24.9 is considered overweight.
- An adult who has a BMI of 25-29.9 is considered moderately obese.
- A waist circumference of > 90 cm ( 35.5”) for men and > 80 cm ( 31”) for women are considered at risk from obesity-related diseases. ( WHO figures for Asians)
For children and adolescents (aged 2–19 years), the BMI value is plotted on the US Center for Disease Control growth charts to determine the corresponding BMI-for-age percentile.
- Underweight : less than the 5th percentile
- Healthy weight : 5th percentile to less than the 85th percentile
- Overweight : 85th to less than the 95th percentile
- Obese: equal to or greater than the 95th percentile
Being overweight puts added pressure on the body's ability to properly control blood sugar and therefore could provoke development of diabetes. Almost 90% of people with type 2 diabetes are overweight.
While the mechanisms underlying the obesity-carcinogenesis relationship are not fully understood, sufficient evidence exists to support recommendations that adults and children maintain reasonable weight for their height and ages for multiple health benefits, including decreasing their risk of cancer.
Obese children are more likely to be obese as adults, hence they are at increased risk for a number of diseases including: stroke, cardiovascular disease, hypertension, diabetes, and some cancers.
Consistent self-monitoring of foods eaten, of eating behavior and physical activities as well as weekly weighing through observation and recording has been shown to :
- promote effective weight control
- improve commitment to change
- increase understanding of eating and activity pattern
- increase feelings of control
A low fat diet is the best way to manage obesity.
Statistics show that obesity rates have doubled in the last 20 years, coinciding with the low-fat revolution. Studies show that in the 1960s, western countries ate 45% of their calories from fat and obesity rate was a low 13%. Today, fat intake is 33% of total calories, yet prevalence of obesity is 34%.
Fewer calories are burned at night than during the day.
Many people believe that they shouldn't eat at night, because calories consumed then won't be burned the same way that calories are burned during the day. This is not true. The body burns calories the same way regardless of what time it is.The real reason nighttime eating is a problem is that most people have met their basic calorie needs for the entire day by the time they finish eating dinner. Any evening snacking results in excess calorie consumption and therefore, weight gain. (Redmond, 2010)
Can someone be overweight yet healthy?
Those engaged in regular exercises and sports are often overweight on the weighing scale and in their body mass index ( BMI) because they have increased fat free muscle mass and bone mineral content. Yet they have lower risk for disease. A healthy lifestyle is what makes the difference. Physical activity , appropriate calories and fat for body’s needs , and the right behavioral patterns are elements of a healthy weight.
Frequently Asked Questions
Which is more critical in a calorie controlled diet : amount of fat or type of fat ?
The position paper of the American Dietetic Association ( ADA) recommends 20% to 35% of energy with emphasis on the reduction in saturated fatty acids and trans fatty acids , and an increase in omega-3 fatty acids. This means a diet high in fruits and vegetables, whole grains, legumes, nuts, lean protein (ie, lean meats, poultry, and low fat dairy products), fish (especially fatty fish high in omega-3), together with the use of olive/canola oils and nonhydrogenated margarines , low in trans fatty acids. However, the amount and type of fat should be managed within the context of a nutritionally adequate diet that is consistent with energy needs for maintenance of a healthy body weight. Hence, even with a balanced fat amount and type, total calorie intake and output remain top priority.
Why is portion control so important as compared to serving size ?
Portion size is the amount of a single food item served in a single eating occasion, such as a meal or a snack. Many people confuse portion size with serving size, which is a standardized unit of measuring foods—for example, a cup or ounce, usually found in labels of processed foods under Nutrition Facts. Portion size is the amount offered to a person in a restaurant, or the amount a person chooses to eat. For example, bagels or muffins are often sold in sizes that constitute at least 2 servings, but consumers often eat the whole thing, thinking that they have eaten 1 serving. They do not realize that they have selected a large portion size that was more than 1 serving.
I am pregnant and obese. Should I lose some weight?
Although obesity during pregnancy increases risk for preeclampsia, cesarean delivery, small for gestational age births, and large for gestational age births, gestational diabetes mellitus, weight loss is not recommended during pregnancy. Efforts should be directed towards limiting pregnancy weight gain to less than the current recommended level of 15 pounds or no weight gain at all. Focus on healthy eating.
What challenges face the health professional in treating obesity?
Experts say there are two challenges :
1. Reduce excess energy stored in body fat without disproportionate loss in lean tissue associated with weight loss.
2. Incorporate motivational interviewing into behavioral change.
How does an adipose tissue in the body look like?
Nature Reviews. Nature Publishing Group. 2006.
Division of Nutrition, Physical Activity and Obesity, National Center for Chronic Disease Prevention & Health Promotion. http://apps.nccd.cdc.gov
Kris-Etherton and S. Innis. ADA Position Statement "Dietary Fatty Acids" Journal of the American Dietetic Association. September 2007 .
Research to Practice Series, No.2 May 2006 National Center for Chronic Disease Prevention and Health Promotion Division of Nutrition and Physical Activity
Thornton YS , C.Smarkola et al. "Perinatal Outcomes in Nutritionally Monitored Obese Pregnant Women: Journal of the National Medical Association. June 2010