Answer to Question 1
The reference standards most commonly used to assess body weight are height-weight tables and BMI. Because it is based on the ratio of weight to height, BMI is a better indicator of obesity than weight alone. The cutoff values for BMI classifications (underweight, healthy weight, overweight, and obese) are based on the association between BMI and weight-related morbidity and mortality. Most medical organizations, including the U.S. Centers for Disease Control and Prevention (CDC), use the following BMI criteria to assess body weight in adults.
Underweight: <18.5 kg/m2
Healthy weight: 18.5-24.9 kg/m2
Overweight: 25.0-29.9 kg/m2
Obese: >30 kg/m2
People with a low BMI (<18.5 kg/m2 ) typically have low amounts of body fat, whereas those with a high BMI (>25.0 kg/m2 ) tend to have higher amounts of body fat. Because each BMI unit represents 6-8 pounds of body weight for a given height, an increase in just two BMI units represents a 12- to 16-pound increase in body weight.
Answer to Question 2
Weight-loss plans that drastically reduce caloric intake and offer limited food choices often leave people feeling hungry and dissatisfied. Instead, those that allow moderate caloric intake and encourage people to eat foods that are healthy and appealing tend to be more successful. Contrary to popular belief, it is not necessary to avoid foods that contain fat in order to lose weight. In fact, many fat-reduced and fat-free foods are high in refined carbohydrates (both starch and added sugars), which can also be detrimental to health. A key recommendation in the 2015 Dietary Guidelines for Americans is for people to develop eating patterns that emphasize a variety of nutrient-dense foods within all food groups, but at an appropriate level of calories. Limiting intake of foods high in saturated fats,transfats, added sugars, and sodium is still advised.