The Fundamentals of Weight Loss


Part 1: The Basic Premise of Weight Loss

The Big Picture

Your body expends (or “burns”) a certain amount of energy every day, an amount known as your daily energy expenditure (measured in calories). The amount of calories in your daily energy expenditure depends primarily upon your individual genetics, amount of muscle mass, and physical activity level. For example, those with relatively high amounts of muscle mass and high levels of physical activity will expend more energy in a day than those with relatively low amounts of muscle mass and low levels of physical activity. You can increase your daily energy expenditure by increasing your level of muscle mass (via strength training and the appropriate nutrition) and physical activity (by moving more). Genetics, of course, cannot be altered (yet).

In order to meet your daily energy requirements (i.e. replenish the calories lost through your daily energy expenditure), you must consume calories by eating food. To determine the amount of calories in any given food, one can read food labels, or use nutritional information database websites like Calorieking.com or Myfitnesspal.com.

The Concept of Energy Balance (Neutral, Positive, and Negative)

      • If you consume the exact amount of calories that you expend daily, your body weight will not change.
                o This scenario is called a neutral energy balance.

      • If you consume more calories than you expend daily, your body weight will increase.
                o This scenario is called a positive energy balance.

      • If you consume fewer calories than you expend daily, your body weight will decrease.
                o This scenario is called a negative energy balance. This is where fat loss occurs.

The above bullet-ed facts are simple, but often forgotten in the sea of misinformation created by popular culture, supplement companies, and fitness media. Think of your body as a closed system. If more energy exits the body than enters the body, weight will be lost. If more energy enters the body than exits the body, weight will be gained. Losing weight always comes down to this principle.

The basic premise of weight loss: weight loss occurs when you consume fewer calories than you expend in a day. When you do this, you place your body in a negative energy balance, which leads to the burning of fat tissue. Fat tissue is broken down and “burned” in order to meet daily energy requirements.

Here is a simple example:

  • An individual expends 2500 calories of energy every day.
     
  • Therefore, the individual will lose weight if he/she eats less than 2500 calories per day.
     
  • If the individual eats 2250 calories a day, there is a deficit of 250 calories in relation to the amount of energy that the individual expends in a day (which is 2500 calories).
     
  • Where does that extra 250 calories come from? It comes from the “burning” of mostly fat tissue, along with other energy stores in the body*.
     
  • The breaking down (or metabolizing) of fat tissue releases the energy that the body needs in order to meet its daily energy requirements. Since the body isn’t eating food from the external environment, it “eats” food from its internal environment.

By understanding the above narrative, you can see that losing weight is simply a number game. Once you pinpoint your daily energy expenditure, you just plug in the right number of calories to be consumed daily, and the weight will come off. Again, losing weight always comes down to the principle of “energy in vs. energy out”.

*Slow and steady caloric reductions lead to the loss of primarily fat tissue, although other energy stores and forms of body tissue (like muscle) are broken down in the weight loss process as well. Certain measures can be taken to encourage greater fat breakdown and less muscle breakdown, but that is for another article.

Factors that Affect Daily Energy Expenditure (DEE)

  • An increase in muscle mass will lead to an increase in DEE
  • An increase in physical activity will lead to an increase in DEE
  • Consuming stimulants (e.g. caffeine) will lead to a small temporary increase in DEE
  • As the body ages, the DEE decreases
  • Males, in general, have greater metabolic rates than females (due to higher levels of muscle mass and hormonal differences), leading to a greater DEE
  • Females, in general, have lesser metabolic rates than males (due to lower levels of muscle mass and hormonal differences), leading to a lesser DEE
  • Some individuals are genetically predisposed to having a greater DEE than others (e.g. two individuals may share the same age, gender, muscle mass level, physical activity level, but one may have a significantly greater DEE due to a genetic difference)

When you understand the above factors, you can see why young athletic men with relatively large amounts of muscle mass need to eat much more than sedentary older women with relatively low amounts of muscle mass.

Weight gain scenario:

Weight Loss Scenario:


Part 2: How to Determine your Daily Energy Expenditure

The Question

In the article “The Basic Premise of Weight Loss” it was stated that losing weight is simply a number game once you know what your daily energy expenditure is. This article provides an answer to the question, “what is my daily energy expenditure?” From this point forward, “daily energy expenditure” will be referred to as “DEE”.

Online Calculators

There are several online calculators that can help you better understand what your DEE is. Simply internet-search “daily energy expenditure calculator”. While these calculators aren’t perfect, they can offer a good starting point by helping you get a better idea of what your DEE is. The process of determining your DEE is just that – a process. When attempting to lose weight, you may have to re-estimate your DEE over time in order to get better results. 

Your DEE is not a rigid value; it constantly changes depending on your activity level and other factors. However, for all intents and purposes for weight loss, it can be viewed as a single undeviating value. Keep in mind that if your body experiences significant changes (e.g. muscle gain/loss, fat gain/loss, or more/less physical activity) your DEE will change significantly and will need to be re-assessed. In the article, there is a list at the end entitled “Factors that Affect Daily Energy Expenditure (DEE)”.

An Individualized Method (homework required)

Another more effective method, albeit more time-consuming, is the individualized approach to determining your DEE:

  • First, you must be sure you have been maintaining the same body weight and physical activity level for         at least a month.
     
  • Next, for one week, write down everything you eat (i.e. what you eat, and how much of it). Do NOT change your dietary habits or physical activity level. You simply want to collect information.
     
  • Use a food scale, food labels, and a free online nutritional information database to find out how many calories you consume every day. It is best to stick to just one database for consistency.
     
  • At the end of the week, take an average of how many calories you consumed in a day.

Here is an example:

[The average in this example is 2400 calories consumed daily.]

  • Not only is this a great method for estimating your DEE, it’s also a great practice in mindful eating (i.e. becoming more aware of what you are putting in your body). Mindful eating is an essential component in the process of losing weight and maintaining a healthy body weight.
     
  • For this method to work, you have to be completely honest when collecting the caloric information. Don’t omit anything. You may be surprised how many or how little calories are in some foods.

While this method is time consuming, it gives you a great individualized baseline of how many calories you consume in a day. Once again, it is very important that you do not change your dietary habits in any way when collecting calorie information. The goal of this method is to understand how many calories you need to eat to maintain your body weight. Once you have that piece of information, you can create a caloric deficit to elicit weight loss.

If the individualized method is too time consuming, simply use an online calculator at first. However, if you aren’t having success losing weight when using the DEE value from an online calculator, try the individualized method.  The individualized method tends to be much more accurate, and it trains you to be more mindful when eating. For those reasons, the individualized method is far superior to online calculators. 

A Practical Example

Here is an example of how your DEE is used in weight loss (the same example I used in “The Basic Premise of Weight Loss”):

  • An individual’s DEE is 2500 calories.
     
  • Therefore, the individual will lose weight if he/she eats less than 2500 calories per day.
     
  • If the individual eats 2250 calories a day, there is a deficit of 250 calories in relation to the amount of energy that the individual expends in a day (which is 2500 calories).
     
  • Where does that extra 250 calories come from? It comes from the “burning” of mostly fat tissue.
     
  • The breaking down (or metabolizing) of fat tissue releases the energy that the body needs in order to meet its daily energy requirements. Since the body isn’t eating food from the external environment, it “eats” food from its internal environment.

Something Simple to Consider

You don’t necessarily need to know what your DEE is in order to lose weight. You can simply eat less, move more, and see how that works. In fact, consistently eating less and moving more is a viable weight loss method that works well for many people. The purpose of this article is to reduce guesswork and help you be more efficient with your efforts, but only use the information if necessary. It is best to keep things as simple as possible, as long as you are getting results. If it isn’t broke, don’t fix it. But if you aren’t getting the results you want, something needs to change. When people aren’t getting results in a weight loss program, taking a closer look at caloric intake (e.g. counting calories and/or keeping a food journal) is their best bet. Keep in mind that counting calories and keeping a food journal aren’t things you have to do forever. After several months of doing so, you will be more informed in your food choices, and you will have a better intuitive sense of how much you are eating.

Summary

The following image summarizes how to use your DEE to lose weight. Your DEE typically decreases when losing weight due to the loss of fat and muscle. Reductions in your metabolic rate also occur when you eat less than you normally do for prolonged periods of time. Therefore, your DEE needs to be re-assessed throughout the process of weight loss in order to elicit consistent results. For example, your DEE may be 2500 calories when you start losing weight, but 3 months in, it may be 2300 calories. Therefore, adjustments in your caloric intake will need to be made accordingly. A caloric intake of 2300 calories would cause weight loss for the first 3 months, but after 3 months, your weight would remain the same.


After reading the above two "Fundamentals of Weight Loss" articles, explore the following articles for simple advice on creating a healthy weight loss plan.