Understanding Energy In Your Diet
According to the energy balance equation, your body gains energy when you intake more energy through your diet than you expend through physical activity. That’s why the main point of most diets is to limit your energy intake through counting carbs or calories.
It seems like a few years ago all of the diets were about counting calories and now they’re all about limiting carbohydrates. But you should you limit carbs or calories? And, if they’re both units of energy what’s the difference? This article will discuss the difference between carbs and calories, how they impact your diet, and how or why you should watch them.
Calories Are Energy, Right? Yes.
To set the record straight, carbs and calories are not both units of energy. We’ll start with calories and talk about carbohydrates in a little bit. 
Calories are the units of energy, not carbs. A single calorie is the amount of energy that it takes to raise the temperature of one gram of water by one degree Celsius. This is a very small amount of energy, so when you read the nutrition label on your food, what they call “Calories” (with an upper-case C) is actually the number of kilocalories (that is, one thousand lower-case c calories). That doesn’t mean that the food companies are trying to lie to you and get you to eat more calories.
They do it because it would be tedious and useless to try to count actual lower-case c calories. Don’t worry about keeping track of whether we’re talking about calories or kilocalories in this article though. Because we’re talking about calories as a unit of energy, it doesn’t really matter which scale we’re talking about, as long as you understand what calories are and why they’re important.
Carbs Are Energy, Right? No.
As mentioned above, the carbohydrate is not a unit of energy like the calorie is. The carbohydrate is a class of nutrient, along with proteins, fats, vitamins, minerals, and water. Carbohydrates, proteins, and fats are all called “energy-yielding nutrients” because the body can break them all down to release calories.
Of the energy yielding nutrients, proteins and carbohydrates both release one 4 calories per gram, while fat releases nine calories per gram.
So Why Are Carbs So Special?
You might be wondering, if fat contains more than twice the calories per gram, why do all of these diets have us watching carbs? And that’s a good question.
The first reason is that the average person has much more carbohydrates than fat in their diet. We tend to think of carbohydrates as coming from grains, like pastas and breads. These are sources of carbohydrates, but carbohydrates also come from sugars. Grains are a source of complex carbs, which your body breaks down over time. Sugars are a source of simple carbs that your body doesn’t have to break down.
Sugars are naturally occurring in sources like fruits, but they’re also added to just about everything. If you put a store-bought sauce on your pasta, you’re putting carbs on carbs. If you put jam or jelly on your bread, you’re putting carbs on carbs. And don’t even get us started on sources like soda and junk food.
When you eat whole grains, you’re not just getting carbs. You’re getting fiber, vitamins and minerals. All of these nutrients can also be found in other foods that don’t have as many calories, like vegetables, which often have no carbs at all.
Fat, on the other hand is far scarcer in our diet and its benefits cannot be found elsewhere. We usually don’t think of fat as being good for us, but it’s in every cell of our bodies, and is very important to the nervous system. While some fats are better than others and you should be careful about how much you get of each kind, carbs are simply more expendable in our diets.
Hopefully, this article has helped you to understand the difference between carbs and calories, as well as why most diets these days have you counting carbs. Remember, however, that a balanced diet and plenty of exercise is better for you than a diet that tries to eliminate fats or carbs or calories and promises a quick solution.