Obesity and Weight Loss Equation Soap Box, Part 1

My last Straight Talk, “Obesity: Facts about Fat, “Obesity: Facts about Fat,ended with the following statements:

“If you have been overweight or obese for a long time, you may very well have metabolic issues that warrant professional intervention. This is a matter of life and death and should not be taken lightly.”

That edition also pointed out that calorie intake with a diet rich in refined carbohydrates and fats is the main contributor to the high obesity numbers.

Weight loss is not necessarily rocket science. If you eat too much and don’t find ways to burn off the calories you consumed, you’ll gain weight. Allow me to stand on my favorite soap box and share some information with you.

I often hear this common excuse from patients who are unsuccessful at losing weight: “I can’t lose weight because it’s in my genes.” Maybe, but maybe not.

The origin of obesity has been debated for years and countless explanations for obesity have been proposed. But after many studies, a simple and concise way to classify the origin of one’s obesity is to break it up into two basic types: exogenous and endogenous obesity.

Endogenous obesity is caused by genetic predisposition.

Exogenous obesity is associated with your calorie intake exceeding energy expenditure and a sedentary lifestyle.

To accurately determine why a patient is obese and to plan weight management strategies to help the patient, health care professionals must collect a thorough medical history on the patient, including age at onset of weight gain, previous weight loss attempts, change in dietary patterns, history of exercise, current and past medications, and history of smoking or smoking cessation.

For healthy individuals, proper diet and exercise throughout life will help prevent obesity. For individuals older than 75, excess body weight does not increase risk of death.

Weight loss can improve or prevent many obesity-related risk factors for cardiovascular disease. Benefits include:

  • Decreased blood pressure if yours is high;
  • Decreased incidence of diabetes and insulin resistance;
  • Improved cholesterol numbers;
  • Reduced C-reactive protein concentration (a marker of inflammation);
  • Improved endothelial function (affects circulation).

If these benefits don’t convince you to lose weight, consider the down side. Well-controlled studies have shown that obesity increases the risk of diabetes 20 times and also the risk of developing high blood pressure, heart disease, stroke, gout, gallstones, depression and certain cancers.


Calorie input in = Calorie input out

It’s a simple formula, a mathematical way of saying you cannot expect to lose weight magically without burning it off in some way. How do we do this?  Exercise and diet changes.


Why is it so hard to lose weight? To start, average daily caloric intake in the U.S. has increased by 500 calories daily since 2000.

Perhaps 500 calories doesn’t seem high, but 500 here and 500 there add up over time, so maintaining caloric balance is important to maintaining healthy weight.

Even for people with normal weight and body mass (BMI), energy expenditure still needs to equal caloric intake to prevent slow weight gain over time. So, balancing caloric intake requires people to both limit their typical caloric consumption and engage in physical activity.

Calculating total energy expenditure for recommended daily caloric intake is based on age, sex, weight, and activity level. Calculating one’s actual daily caloric intake can be done by recording what you eat in a food diary, or online assessment tools and smartphone aps (that determine caloric intake of different foods and beverages). Counting your calories is fairly easy these days.

However, the bigger picture people forget is that we are not all created equal in size or in how we metabolize food. How many calories you need to consume in a day is based on your current activity levels and/or exercise goals.

Total energy expenditure = Basal metabolic rate x activity factor

Your Basal Metabolic Rate (BMR) is the amount of energy you expend each day when at rest. Gender, age, height and weight are important for this calculation. The World Health Organization published a revised equation for estimating energy expenditure. We found an easy calculator and encourage you to use it to see how many calories you need today to stay the same size. (Of course, results given by ANY calculator should be used as a guide only and should not replace medical advice. You should always speak to your doctor or qualified health professional before making any dramatic changes to your lifestyle.)

Calculate your Rate Here with this online calculator. (NOTE kcal=1 calorie)

As an example, we imagined a 5’3”, 120-pound woman who engages in moderate activity level of exercise per week (ie, exercise for at least 30 to 60 minutes three to four times weekly.) Her body will burn 1265 calories each day if she engages in no activity for the entire day. Her calorie requirement to maintain her weight is 1961 calories… assuming she consistently maintained the same moderate exercise activity level. If she increased her caloric intake and/or lowered her physical activity level she may gain weight.  If she completely stopped exercising (sedentary lifestyle), she would gain weight if she consumed 1518 calories a day. The average woman in the U.S. consumes > 2000 calories daily, which is why so many women are considered obese. There are multiple factors in a sedentary lifestyle that have a negative impact and we will cover this in the next part of this series.

I encourage you to play with this calculator. You will notice that we really do not need that many calories and so we MUST get as many nutrients out of the calories we consume as possible. Quality food is the fuel for your body.

Quality food choices should include:

  • 45 – 65% from carbohydrates. Ideally, select whole grain and low glycemic index carbs (eg. fruits and vegetables).
  • High glycemic index carbs (eg. pizza, rice, pancakes) are associated with risk of developing coronary heart disease, type 2 diabetes mellitus, and some cancers.
  • 10 to 35% from protein (fish, poultry, eggs, peas, unsalted nuts).
    Avoid or limit proteins with trans and saturated fats, including red and processed meats.
  • 20 -35% from fat – The type of fat is more important than the amount of total fat. Trans fats contribute to coronary heart disease vs. polyunsaturated fats which are protective. Long-term consumption of fish oil and Omega-3 fatty acids reduces the risk of cardiovascular disease. The recommendation for most adults is one to two servings of oily fish weekly.
  • Fiber – The recommended amount of dietary fiber is 14 grams per 1000 calories, or 25 g per day for women and 38 g per day for men. Replace refined grains like white rice, white bread or pasta with whole grains such as brown rice, whole wheat bread or wheat pasta, which have higher fiber content.

Cardiovascular disease: High fiber intake is associated with a 40 to 50 percent reduction in the risk of CHD and stroke compared with low fiber intake. It is also associated with lower cardiovascular and all-cause mortality in patients who have had a myocardial infarction. High fiber diets are protective against CHD by controlling risk factors, such as lowering blood pressure, insulin levels, and improving lipid profiles.

Diabetes mellitus: Fiber consumption from grains is beneficial in controlling blood glucose in patients with diabetes, proving a protective effect against the establish course of the disease.

Cancer: Low of dietary fiber are associated with development of colorectal cancer.

Also remember micronutrients such as sodium are needed in very small amounts. The daily recommended intake is less than 100 meq/day (2.3g of sodium or 6g of sodium chloride). A high dietary intake of sodium is associated with the development of hypertension and cardiovascular disease. Reduction in sodium intake decreases the risk of cardiovascular events, including death.


Two of our favorite diets are:

The DASH diet (Dietary Approaches to Stop Hypertension) consists of four to five servings of fruit, four to five servings of vegetables, two to three servings of low-fat dairy per day, and <25 percent dietary intake from fat. The DASH diet has been studied in both normotensive and hypertensive populations and found to lower systolic and diastolic pressure more than a diet rich in fruits and vegetables alone. The combination of low sodium and DASH diet resulted in further decreases in blood pressure, comparable to those observed with antihypertensive agents.

The Mediterranean diet is typically high in fruits, vegetables, whole grains, beans, nuts, and seeds. Include Olive oil, an important source of monounsaturated fat is included in moderate amounts, as is low to moderate wine consumption. There are typically low to moderate amounts of fish, poultry, and dairy products, with little red meat. The Mediterranean diet is associated with improved health status and reductions in overall mortality, cardiovascular mortality, cancer mortality, and incidence of Parkinson’s disease and Alzheimer’s disease. However, it remains uncertain which components of the Mediterranean diet offer the protective benefit, or if the benefits result from an aggregation of effects.

This is a lot to absorb, so next time we will talk about weight loss programs, medications and surgery. We will also cover some tips and strategies to help you burn more calories – the other side of our weight loss equation.

Until next time!

Stephanie Coulter, MD

Special thanks to Keri Sprung and Dr. Karla Campos for her assistance in writing Straight Talk.

Do you have a topic that you would like to learn more about from Dr. Stephanie? Send us an email at women@texasheart.org and your question may be the next Straight Talk topic!