Integrative Biology 131: General Human Anatomy. Fall 2005. Professor Marian Diamond. The functional anatomy of the human body as revealed by gross and microscopic examination.
BMI: three simple letters that can mean so much. BMI stands for Body Mass Index and it’s becoming a universal tool to measure body “fatness” even though it doesn’t actually measure body fat like using a caliper or underwater weighing (also known as hydrostatic testing.) However, despite it’s imperfections, BMI is a fairly good indicator of body composition for most people. And as such BMI has become a prevalent health screening method. Understanding what exactly BMI measures, the reliability of BMI results and how to interpret those results, will go a long way in providing the information you need to take steps to improve your health.
What exactly does BMI measure?
If BMI doesn’t really measure body fatness, what exactly does it measure? BMI measures the mass of the body in relation to height and weight. And by taking this calculation one can make a relatively accurate assumption of body fat percentage. So for example, if you calculate your own BMI you will learn whether your current weight in relation to your height is considered underweight, normal, overweight or obese.
In addition to learning what weight classification you fall in, a BMI number can (hopefully) give you the motivation needed to lose weight: the only way to lower your BMI is to lose weight! To lose weight you need to have a calorie deficit each week of either 3500 (one pound lost a week) or 7000 (two pounds a week lost). Any more than two pounds and it’s really just water.
To determine your overall calorie deficit you’ll first need to know your BMR. BMR stands for Basal Metabolic Rate. This is the amount of daily calories burned when a person is at rest. In other words, if you lay in bed all day, this is the amount of calories you would need to consume to maintain your current weight. Then your BMR and your current activity level are considered to determine your TDEE. TDEE stands for Total Daily Energy Expenditure.
So for example, if your BMR is 1596 and your TDEE is 2752, to lose one pound a week you need to eat no more than 2752 calories a day and for you to lose two pounds a week you need to eat no more than 1752 calories daily. Once you know these numbers you can chart a path forward and see how long it will take to reach your goals.
Diet-to-Go does not recommend going below 1200 calories a day. If you want to expedite your weight loss, don’t cut more calories out, burn more.
How reliable is BMI?
BMI is good but it’s not perfect. BMI is determined by dividing a person’s weight in pounds (lbs) by their height in inches (in), squared and then multiplied by 703. The formula:
BMI = weight / [height (in inches)]2 x 703
You’ll notice this formula doesn’t take age or gender into consideration. It also doesn’t account for the amount of muscle mass an individual may have; many athletes with a large percentage of muscle mass, may measure a high BMI even though they do not have excessive amounts of body fat. It’s also important to note some other variations:
At the same BMI, women tend to have more body fat than men. (Sorry ladies, it’s just the way we’re built.)
At the same BMI, older people, on average, tend to have more body fat than younger adults.
Athletes may have a high BMI because of increased muscularity rather than increased body fatness.
What does a high BMI mean?
A BMI of 18.5 to 24.9 is considered healthy, a BMI of 25 to 29.9 is considered overweight and a BMI of 30 or more is considered obese. If you score a BMI of 25 or above means you are at a much higher risk of suffering from a whole host of diseases including:
Diabetes
Heart disease
Stroke
Cancer (breast, colorectal, endometrial and kidney)
Is BMI the last word?
The good news is, just because you have a high BMI, you are not necessarily going to have a stroke or experience any ill affects. The CDC, National Heart, Lung and Blood Institute and other nationally respected institutions contend that BMI is only one factor impacting the risk for weight-related diseases. The two other main predictors include waist circumference and other existing risk factors (e.g., high blood pressure, smoking, etc.).
How to lower your BMI?
Lose weight. Assuming you are not one of those highly muscled athletes and you are registering a high BMI, the only way to lower this number is by losing weight. We all know losing weight can be difficult, and there is no magic pill, but by making small, sustainable changes to your daily eating habits, you can and will lose weight.
To expedite your weight loss, exercise. Not only can exercise help you lose weight faster but it also helps you maintain the weight you’ve lost. When you engage in exercise your body burns calories during the activity as well as after the activity. And as you increase your muscle mass you will burn even more calories as muscle tissue burns more calories at rest than does fat.
Remember that losing weight and keeping it off means making smart choices and establishing sensible eating and exercise habits for the long haul.
Stress is ubiquitous and on the rise. How we learn to manage it can have profound effects on our health and well being. This series explains how our bodies experience stress and demonstrates effective strategies to help you thrive in a fast-paced world. On this edition, Richard Harvey discusses strategies to reduce stress beyond medication. Series: “UCSF Mini Medical School for the Public” [3/2008] [Health and Medicine] [Show ID: 13720]
The key to losing weight, and keeping it off, isn’t some secret potion or magic pill. The way to lose weight is by breaking bad eating habits and in exchange, adopting good ones. Despite promises by many advertisers, losing weight isn’t a quick fix. Losing weight (and keeping it off) is about establishing a common sense approach to healthy eating and exercise. It’s about changing habits in a way that is achievable and sustainable over the long haul. Know that with time and effort you can change your eating habits and lose weight for good!
Most Common Bad Eating Habits
Skipping Meals
It seems like such a good idea: to save some calories, skip a meal. Unfortunately our bodies are not so easily tricked. When you skip meals you are actually decreasing the rate of your metabolism. Skipping a meal every once in awhile is not a big deal, but when we do it on a regular basis we are setting ourselves up for failure. Over time, skipping meals triggers your body’s “starvation mode” where the body tries to compensate for the low calories. Your metabolic rate can actually decrease as much as 10-15%, and your body will hold onto the fat and burn lean muscle instead. In addition, skipping meals can make you excessively hungry so when you do eat your next meal, chances are, you’ll overeat.
Good habit: Instead of skipping meals to save calories, strive to burn more calories each day by sneaking in exercise whenever you can. Not only will exercise help you burn more calories while you’re actually exercising but after the workout as well. Plus working out will actually give you more energy that you can use to make healthy food choices.
Eating Distracted
In a world of instant messages, “real time” updates and 24/7 Tweets, sitting down for a relaxing, uninterrupted meal is not always, or ever, possible. As a result we often eat in the car, while the TV is on or at our desk at work. Eating distracted makes it a lot easier to eat more.
Good habit: Eat mindfully. Don’t just go through the motions, actually plan and be conscious of your eating. Turn off the TV, radio and computer. Walk away from your desk at work. Even if it’s just for a few minutes, make mealtime about eating. Taste your food. Chew. Enjoy.
Eating Large Portions
From soft drinks to muffins to sandwiches, portion sizes are completely out of whack. The amount of food we now view as “normal” has grown way out of proportion. In order to control overeating, and overcome this bad eating habit, we need to recognize how much we are actually consuming. We need to understand that a portion of food we are served at a restaurant, or that we prepare for ourselves may be more than a single serving. Serving size and portion sizes are two completely different things and you need to count the calories accordingly.
Good habit. Retrain your mind as to what is a normal portion size. Trick your mind into perceiving bigger portions by serving your meals on a small plate or bowl. Avoid eating foods right out of the box or bag. Separate your food into individual portion sizes when you first get home from the store, before you even put the items away. Having your food already portioned out makes eating a reasonable amount a no-brainer.
Using Food to Relieve Stress
Deadlines at work, demands at home…stress can be, well, a stressful thing. Unfortunately many people turn to food to relieve stress. Using food in this way, and really any way other than satisfying our hunger, leads to weight gain.
Good habit: When feeling stressed out, find ways to relax that don’t involve food. Go for a walk. Call a friend. Lose yourself in a good book. There are so many options. Making these choices a habit over mindlessly reaching for food after a bad day will go a long way in helping you control your weight.
Late Night Eating
Eating late at night is another one of those bad eating habits that is really quite terrible but is easy to “sweep under the rug.” We usually don’t eat late night unless we’re either totally by ourselves in which case nobody else knows what you’re doing, or we’re in a social situation where everyone is eating. Either scenario leads for the acceptance of this bad eating habit.
Good habit: Once dinner is over and the kitchen cleaned, turn off the lights. The kitchen is now closed. Make it off limits until the next morning. Another good tactic, brush your teeth immediately following dinner. When your teeth feel all nice and clean, you’ll be less likely to want to eat and lose that “minty fresh” feeling. If you still find yourself being drawn to the fridge after hours, go to bed! Making sure you get enough sleep will do wonders for your weight control. Plus, if you are sleeping, you can’t be eating.
Habits Can Be Changed!
Expert opinion varies on how long it takes to change a habit. But the good news is, habits are changeable. You can always break a bad habit and in its place establish a good one! You just need to make the commitment to do it and be consistent. Know that your hard work will pay off eventually.
Integrative Biology 131: General Human Anatomy. Fall 2005. Professor Marian Diamond. The functional anatomy of the human body as revealed by gross and microscopic examination.
Explore measures that can be taken to not only live longer but also live better with Dr. Ellen Hughes who describes the need for sleep to achieve wellness and health. Series: “UCSF Mini Medical School for the Public” [6/2008] [Health and Medicine] [Show ID: 14532]
