Although it's not strictly necessary, many people believe in counting calories when they diet or decide to enter the cutting phase of their bodybuilding cycle. It is even helpful for those during bulking so that they can see if they are hitting your daily target. Although it requires a degree of effort, it is an effective way to know exactly what you are putting into your body. It has been shown that calorie counting, when combined with exercise was effective in regulating the amount of food consumed, and hence aided in weight loss (Rejeski et al, 2011).
What is a Calorie?
Before we dive into the nitty gritties of calorie counting, it is important to know what a calorie is. Long story short, a calorie (cal) is a unit to measure the amount of energy that can be obtained from food. Nutrients such as carbohydrates, fats, proteins, fibre, organic acid, polyols, and ethanol can all contribute to the energy content of food to varying degrees.
One thing that needs to be cleared up is actually the word "calorie" itself. Strictly speaking when someone uses the word "calorie", in the context of food, is actually a kilocalorie or Kcal (ie 1000 cal). For reasons unknown, it has been tradition within the English language to drop the kilo- prefix from everyday use of the word. So you can generally get away with saying "calorie" as a synonym for "kilocalorie". In this article whenever you see the word "calorie" from here, you can assume it to mean "kilocalorie".
What slightly complicates this matter is that, depending on the country you go to, food energy can also be measured in joules (J) or kilojoules (KJ). For example KJ is the standard scientific measure for energy, and it is also the official unit used here in Australia. However, because of strong American influences, we often do see things in calories. Do not fret, because there is a simple conversion you can apply. One KCal (or calorie) is equal to 4.18 KJ (round off to 4), or one KJ is 0.24 KCal (round off to 0.2). Knowing these figures off by heart will make life much easier for you if you decide to take up calorie counting.
How to Calorie Count
Now let's get to the actual counting. Counting the calories for certain foods is rather simple. By law, processed and packaged foods need to provide a nutritional label on the packaging that gives information on how many calories (or KJ) the food provides. For fresh foods you would ideally need a kitchen scale to more accurately weigh your foods. If not, it is possible to try to estimate the amount you eat, either through weight or volume (eg 1 cup). With this, you can then use a variety of nutrient databases (NUTTAB for Australians, USDA database for Americans), online calculators, and even phone apps to work out exactly how many calories this particular food is giving you.
It is important to determine the number of calories in each of the foods and drinks you consume during the day. It would be unrealistic to expect to memories everything so it is recommended that you keep a food journal. This can be a good old fashion pen and pad, an Excel spread sheet, or even a purpose designed phone app. At the end of the day the totally number of calories need to be added up so you can see if you're meeting your target. If you are well over or under, you will know to adjust for the next day. Keeping an accurate log also lets you track your progress and how consistent you diet is. After a while, you will become fairly experienced with knowing the caloric content of many foods, and keeping a written log may not strictly be necessary.
Calorie Counting Benefits
With calorie counting, it is possible to determine what goes into your body with a relatively high degree of accuracy. The principles of calorie counting can also be seamlessly applied to pretty much any macronutrient or micronutrient, such as protein, carbs, fats, and vitamins. This will of course require more effort, but it will provide you with a comprehensive log of your daily intake. After a while, calorie counting will teach you a great deal about food and nutrient content. An encyclopaedic knowledge of food is always a useful long term skill to have.
Calorie Counting Negatives
The most obvious downside to calorie counting is the actual effort involved with calorie counting. You do need to have a degree of patience, dedication, some spare time on your hands, and ideally a set of scales. The process is slowest when you're just starting out, but as you become more experienced, it becomes almost second nature.
The accuracy of the count itself is highly dependant on your ability to accurately weigh your food. It could be completely inaccurate without a set of scales for inexperienced people. Furthermore, the accuracy of the nutrient database used may also be poor, so be sure to use a reliable source. Finally, food is not homogenous. For examples, meat has variable amounts of fat, that is sometimes inseparable from the lean, and seasonal differences also occur in the nutrient content of certain foods. This may be an additional source of inaccuracies.
Another potential downside is that it is often hard to count restaurant foods because it is impractical to weigh served food, and it is not always apparent exactly what's gone into the dish. More experienced counters may be able to make some sort of informed guess, but it would be next to impossible for beginner counters. One attractive aspect about fast food restaurants is that they all tend to provide nutritional information on their products, either on the packaging or their website. This makes calorie counting easy if eating fast food.
Calorie (and nutrient) counting is a widely used way to monitor your daily intake and to ensure you are meeting your goals. However, it does require time and effort and may not be suitable for everyone. If you do intend to practice calorie counting, it will teach you a lot about food and nutrition, a valuable skill for life. There are many great books that cover food and nutrition that may be worth investing in, to learn more about applicable approaches to monitoring your weight loss and/or bodybuilding diets.
Rejeski et al (2011), Weight Loss and Self-Regulatory Eating Efficacy in Older Adults: The Cooperative Lifestyle Intervention Program. J Gerontol B Psychol Sci Soc Sci, 66B: 279-286