Nutrition Science and Obesity

10 Questions

What is the approximate body fat percentage for healthy women?

25-30%

How many risk factors for CHD are related to diet?

Four

What is the strongest risk factor for liver cancer?

Alcohol

What is the third leading cause of cancer mortality in men and women?

Colorectal cancer

What was the focus of the first phase of nutrition science in the 20th century?

Discovering and characterizing essential nutrients

What is the primary advantage of maintaining a desirable body weight throughout life?

Preventing and treating type 2 diabetes

What is the formula to calculate BMI with pounds and inches?

BMI= Weight (lb) / Height (in)^2 x 703

In which type of individuals may a normal BMI conceal underlying excess adiposity?

Elderly individuals and persons of Asian descent

What is the percentage of body fat that defines obesity in men?

Greater than 25%

What is another index used to estimate the degree and distribution of obesity?

Waist and hip circumference

Study Notes

Obesity and Body Fat Percentage

Normal, healthy men have a body fat percentage of 15-20%, while normal, healthy women have a percentage of approximately 25-30%.
Obesity is the most common nutritional disorder worldwide and directly or indirectly accounts for a significant portion of health-related expenses.

Phases of Nutrition Science

The first phase of nutrition science involved discovering, characterizing, and synthesizing essential nutrients and describing their deficiency syndromes in detail.
The second phase involved accumulating evidence on the relationships of diet and nutritional status to chronic diseases, such as coronary heart disease (CHD), cancer, diabetes, and other leading causes of death.

Nutritional Influences on Chronic Diseases

Of the seven major risk factors for CHD, four are related to diet: hypercholesterolemia, hypertension, obesity, and diabetes.
Colorectal cancer is the third leading cause of cancer mortality in men and women, and its risk correlates positively with the intake of red and processed meats, obesity, and alcohol.
Obesity increases the risk of liver cancer, with alcohol being the strongest risk factor.
Type 2 diabetes mellitus is strongly associated with obesity, especially abdominal obesity, so maintaining a desirable body weight throughout life is crucial in preventing and treating type 2 diabetes.

Clinical Assessment of Obesity

The body mass index (BMI), also known as the Quetelet index, is commonly used to define obesity, and it correlates closely with the degree of body fat in most settings.
BMI is calculated as weight (in kilograms) divided by height squared (in meters), with a modified formula for pounds and inches: BMI= Weight (IB) / Height (inches) 2 X 703.
However, BMI has limitations, such as overestimating body fat in muscular individuals and underestimating it in elderly individuals and those with sarcopenia.
Alternative indices for estimating obesity include skinfold thickness measurements and anthropometric measures, such as waist and hip circumferences.

Definition of Obesity

For men, a percentage of body fat greater than 25% defines obesity, with 21-25% being borderline.
For women, over 33% defines obesity, with 31-33% being borderline.