Nutrition and Your Body

How can we tell if the Body is Healthy?

One way to assess whether a body is healthy is to determine its body composition — that is, how much of the body is muscle versus fat. There are numerous ways to measure body composition, but the one you may have heard about at the doctor’s office or in the news is BMI, which stands for body mass index. BMI is calculated from height and weight and is an inexpensive, easy screening method for indicating your weight category.

Another way to evaluate body composition is to measure fat directly and assess its distribution. The easiest method is a skinfold test using a caliper — a tool that looks somewhat like a pair of pinchers — to measure the thickness of skin at the back of the arm, the back, and several other areas. This test is inexpensive, non-invasive, and fairly accurate.

The distribution of fat on the body is just as important as the total amount of fat. An easy way to measure distribution is by calculating the waist-to-hip ratio. A greater difference between your waist and hip measurements indicates a pear shape, while little difference between the two suggests an apple shape — a pattern associated with greater risk for chronic disease. Where you carry your weight affects your health.

Balancing Energy Input and Energy Output

The United States has been contending with an obesity epidemic for more than thirty years. The number of people considered overweight or obese has now surpassed the number who are undernourished. There are many reasons for this enormous rise in obesity, but a primary cause is that people are consuming too much and moving too little.

https://www.cdc.gov/obesity/data/prevalence-maps.html

Basal Metabolic Rate

Your basal metabolic rate (BMR) is the number of calories your body burns while at rest. Surprisingly, you burn the largest percentage of your daily calories — about two-thirds — while sleeping or sitting. These calories fuel essential body processes such as brain function, breathing, growth, and repair.

Another important consideration is your ratio of lean muscle mass to body fat. Muscle tissue is metabolically active, meaning it burns more calories throughout the day. Men typically have a larger percentage of lean muscle mass than women and therefore tend to have a higher BMR. Fat tissue, by contrast, is not metabolically active. If you consume more food than you need for energy, your body converts those excess calories into fat. People who are taller or who are pregnant also burn more calories.

While you can calculate how much energy you take in by counting calories, it is harder to know how much you are burning, because calories are expended through three different activities:

• Resting (BMR)
• Physical exercise
• Digesting food

Activity Levels

Sedentary: A lifestyle that includes only the physical activity of independent living.

Moderately active: A lifestyle that includes physical activity equivalent to walking about 1.5 to 3 miles per day at 3 to 4 miles per hour, in addition to the activities of independent living.

Active: A lifestyle that includes physical activity equivalent to walking more than 3 miles per day at 3 to 4 miles per hour, in addition to the activities of independent living.

*Estimates for females do not include women who are pregnant or breastfeeding.

Complete the activity in the blue text box below to determine your individual nutrient needs.

If you want to increase the energy you burn, the most effective approach is to increase your physical activity. However, energy intake and expenditure are regulated by highly complex systems and influenced by genetics, behavior, and the environment. The equation is not simply “energy in = energy out.” Dieting is practically an American pastime, but it is not a solution for poor eating habits or lack of physical activity. There are health risks associated with both being overweight and being underweight. Talk to your physician and a registered dietitian about how to improve your diet and exercise routine to optimize your health.

Disordered Eating

A person with disordered eating has attitudes and behaviors toward their body that range from unhappiness with their body shape to unhealthy eating, dieting, and exercise habits. A formal eating disorder must be diagnosed by a physician or psychologist using the criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), which lists the symptoms associated with each type of disorder.

Anorexia Nervosa

Anorexia nervosa — more often referred to simply as “anorexia” — is a psychiatric illness in which a person becomes obsessed with their weight and with the food they eat. Anorexia results in extreme nutritional inadequacy and, eventually, organ malfunction. The condition is relatively rare: the National Institute of Mental Health (NIMH) reports a lifetime prevalence of 0.9 percent in females and 0.3 percent in males. Even so, it is a powerful example of how a severely unbalanced diet can affect health.

Anorexia frequently manifests during adolescence and has the highest mortality rate of all mental illnesses. People with anorexia consume, on average, fewer than 1,000 kilocalories per day and exercise excessively — a severe caloric imbalance. Some may also engage in binge eating, self-induced vomiting, or purging with laxatives or enemas. The exact causes of anorexia are not fully known, but many factors contribute, including socioeconomic status (it is more prevalent in higher-income families), genetics (it is often passed from one generation to the next), and abnormalities in pregnancy, brain development, the endocrine system, and the immune system.

The primary signs of anorexia include fear of being overweight, extreme dieting, a distorted perception of body image, and depression. Secondary signs and symptoms — related to caloric and nutrient deficiencies — include excessive weight loss, skin abnormalities, diarrhea, tooth decay and loss, osteoporosis, and liver, kidney, and heart failure. Because there is no single physical test that can diagnose anorexia and distinguish it from other mental illnesses, a correct diagnosis requires ruling out other mental illnesses, hormonal imbalances, and nervous system abnormalities through blood tests, urine tests, and imaging.

Treatment of anorexia involves the individual as well as their family, friends, and a psychiatric counselor, and typically includes a dietitian who helps develop dietary solutions that may need to be adjusted over time. The goals of treatment are to restore a healthy body weight and significantly reduce the behaviors associated with the eating disorder. Relapse is common. While many people recover from anorexia, most continue to have a lower-than-normal body weight for the rest of their lives.

Bulimia Nervosa

Bulimia nervosa, like anorexia, is a psychiatric illness with potentially severe health consequences. The NIMH reports a lifetime prevalence of 0.5 percent in females and 0.1 percent in males.

Bulimia is characterized by episodes of eating large amounts of food followed by purging through vomiting, laxatives, or diuretics. Unlike people with anorexia, those with bulimia often have a normal weight, which makes the disorder more difficult to detect and diagnose. Signs and symptoms similar to those of anorexia may be present, such as fear of being overweight, extreme dieting, and excessive exercise. Additional physical signs include gastric reflux, severe erosion of tooth enamel, dehydration, electrolyte imbalances, lacerations in the mouth from vomiting, and peptic ulcers. Repeated damage to the esophagus also puts people with bulimia at increased risk for esophageal cancer.

Bulimia is also highly heritable, is linked to depression and anxiety disorders, and most commonly occurs in adolescent girls and young women. Treatment often involves antidepressant medications and, as with anorexia, has better outcomes when both the individual and their family participate in nutritional and psychiatric counseling.

Binge-Eating Disorder

Like people with anorexia and bulimia, people with binge-eating disorder (BED) have lost control of their eating. Unlike those with bulimia, however, their loss of control is not followed by fasting, purging, or compulsive exercise. As a result, people with BED are often overweight or obese and face chronic disease risks associated with high body weight, such as hypertension, cardiovascular disease, and type 2 diabetes. They frequently experience guilt, shame, and depression, and BED is commonly associated with depression and anxiety disorders.

According to the NIMH, binge-eating disorder is more prevalent than anorexia and bulimia, affecting 3.5 percent of females and 2.0 percent of males at some point during their lifetime. Treatment often involves antidepressant medication along with nutritional and psychiatric counseling.

Orthorexia Nervosa

Orthorexia nervosa is an obsession with healthful eating. The term was coined in 1998. Unlike the eating disorders described above, orthorexia is not currently listed in the DSM-5, which makes it difficult to estimate how many people are affected. Orthorexia may involve the following behaviors:

• A compulsion to check ingredient lists and labels
• Increased concern and stress about the health of ingredients
• Spending a large percentage of time obsessing about your food and what others eat
• Eating a very limited variety of foods due to the elimination of various food groups

PIca

Pica is a psychological disorder in which the person compulsively eats items with no nutritional value, such as dirt, chalk, laundry detergent, or hair. The diagnosis is made from a clinical history of the patient.