Principles of Weight Loss

Weight Loss 101:

Basic Principles of Weight Loss

Weight loss and weight gain depend on the balance of “calories in” versus “calories out.” If you eat more calories than you burn, you will gain weight. If you burn more calories than you eat, you will lose weight. This is the bottom line, regardless of whether factors such as genetics and medications affect how we respond to cues to eat and how we burn calories.

Therefore, to manage weight, you will need to be able to manage what you eat and how you “spend” (burn) calories. You need to learn what kinds of foods should be limited and what foods should be included (everyday foods versus once-in-awhile foods).

What Are Calories?

Calories are the energy currency of your body. We use them to measure the energy we get from food, just as we use dollars to measure how much money we have. When we take in excess calories, we save them in our fat account, much as we save dollars in a savings account. To balance our checkbook, we need to pay attention to how much things cost (how many calories we burn a day) and how much we get paid (how many calories we take in).

People usually get calories from three different sources: carbohydrates, protein, and fat.

  • Carbohydrates have 4 calories per gram. Types of carbohydrates include starches, sugars, and fiber. Some foods that are high in carbohydrates include bread, pasta, rice, and other grains, fruits, and starchy vegetables such as corn, peas, or potatoes.
  • Proteins have 4 calories per gram. Types of proteins include complete and incomplete proteins. Animal products, dairy products, and some dried peas and beans are good sources of protein.
  • Fats have 9 calories per gram. Types of fat include saturated and trans fats, which are linked to heart disease, and polyunsaturated and monounsaturated fats, which are considered “heart healthy.” Oils, nuts, avocados, mayonnaise, butter, margarine, creams, dressings, whole and reduced-fat dairy foods, and fatty meats are some foods that are high in fat.

All of these calorie sources can be used for energy, and all can be saved as fat in your body. Each source has an important job in keeping you healthy, and too much or too little of any one is unhealthy.

Alcohol is also a source of calories. It has 7 calories per gram and does not provide nutrients your body needs. If you have problems limiting the amount of alcohol you drink, you should seek treatment before considering weight-loss surgery.

How Many Calories Make a Pound of Body Weight?

When you eat 3,500 calories more than you burn, you gain one pound. Likewise, you have to burn 3,500 calories more than you eat to lose one pound.

If you want to lose one pound a week, you need to create a deficit of 500 calories a day (500 calories per day multiplied by 7 days equals 3,500 calories for the week). One way you could achieve this deficit is by eating 500 calories less than you burn for the day or by cutting out 300 calories from food and burning 200 calories more than you burn now.

Spending Calories

The calories you burn (“calories out”) are generally spent in three ways:

  • Keeping your body alive: Over half of the calories you burn are used for basic life, including many activities that you don’t even think about. You use calories to make your heart beat, to keep your body temperature comfortable, to breathe, to clean out your blood, to digest food, and to perform many other bodily functions. There is not much you can do to increase the calories you spend here.
  • Performing day-to-day activity: You spend calories when you stand and cook, take a shower, walk to the car, dust, mow the lawn, or perform any of the other activities that are part of your day-to-day life. Small changes in this area can increase how many calories you spend. For example, you can burn more calories by parking farther away from the store and walking the remaining distance or by doing your own housework instead of hiring a cleaner.
  • Engaging in physical activity or “fitness activity”: Finally, you spend calories doing activities designed to increase your fitness and health. All activity burns calories, but activity that makes you breathe harder and break a sweat has extra calorie-burning power. Walking is a great way to burn calories, but you may need to work up to this activity. Fitness activity is an important part of long-term weight management.

Cutting Calories

Although activity is a requirement for weight management, it is not usually the basis for weight loss. Most weight loss has to be accomplished through diet—by decreasing “calories in.”

There are different ways to change your diet and reduce your “calories in,” including (1) structured meal plans or (2) using food records to create a personalized plan. Both of these methods have advantages and disadvantages. Talk to your registered dietitian (RD) to decide which strategy works best for you, to determine your calorie needs, and for sample meal plans

Structured Meal Plan

A structured meal plan states exactly what you can eat each day. Following a structured plan can help you to learn about a balanced diet and portion sizes. Also, you do not have to think about what foods to eat because the diet tells you what to choose.
On a structured meal plan, you will need to measure portions, unless you use prepackaged foods. In either case, your diet will not be as personalized as it would be if you kept food records.

Using Food Records to Create a Personalized Plan

When you keep food records, you can develop your own plan and adjust how many calories you consume based on what you usually eat and your activity levels. To learn about your own diet and how to adapt it to eat fewer calories, start by recording what you currently eat. Your records should include portion sizes and the calories in the foods you eat. The calories in different foods can be found on food labels (note the serving size!) and online at sites like Calorie King ( For instructions on keeping and using lifestyle records, ask your RD for a copy of The Recording Studio handout. You can keep records in a notebook or on a smart phone or computer.

Once you determine what you are eating and where your calories are coming from, you can determine the best ways to reduce your “calories in.” For example, let’s say your food records show that one day you ate the following:



Examples of 500-calorie reductions:

  • Eliminate the bacon (100 calories) and half-and-half (20 calories) at breakfast; have only one doughnut hole for your snack; have a plain hamburger instead of a bacon cheeseburger at lunch.
  • At breakfast, cut the amount of cheese and bacon in half; skip the bacon on the cheeseburger at lunch; have an apple instead of the chips for your snack.
  • Eat a piece of fruit instead of cheese and bacon at breakfast, and skip the snack of doughnut holes.