When it comes to weight, calories are often talked about but frequently misunderstood. Indeed, whether counting calories is actually useful for weight loss is debatable. Read on to learn about calories and their role in weight regulation on low-carb and keto diets.
- What are calories?
- How many calories do carbs, protein, and fat provide?
- Calories count, but they are not the whole story
- Counting calories: yes or no?
What are calories?
A calorie is a unit of energy that your body uses to perform hundreds of tasks. These include voluntary movements like walking, running, and jumping, as well as involuntary ones like breathing, circulating blood throughout your system, and maintaining normal body temperature.
Your body needs a certain number of calories just to keep these involuntary processes going. This is referred to as your basal metabolic rate, or BMR. Your BMR is influenced by many factors, including your age, gender, body composition, and genetics.
You require additional calories for physical activity, including walking. Overall, the more active you are, the more calories you'll need.
How many calories do carbs, protein, and fat provide?
Each macronutrient provides a specific amount of calories:
Importantly, even though fat provides more than twice as many calories as carbs, it's far denser and more filling.
Protein is generally considered the most satiating macronutrient, but it's mostly used for cell repair, maintenance and growth. Thus protein intake is mostly important in order to fill your body's protein needs. Protein is not very effective as a fuel (i.e. as calories). Excess protein has to first be converted to glucose in the liver, in order to be used as fuel. Eating protein in excess of your body's needs is not necessarily a good thing, and it can reduce the effect of a strict low-carb diet. Learn more
Pure fats and oils get 100% of their calories from fat. However, the calories in most foods are a combination of carbs, protein, and fat.
For instance, although eggs are considered a protein food, the majority of their calories actually come from fat. For example, two large eggs provide 146 calories:
- 4 calories from carbs (1 gram) (2%)
- 52 calories from protein (13 grams) (34%)
- 90 calories from fat (10 grams) (64%)
Calories count, but they are not the whole story
Generally speaking, if you take in more calories than your body needs over a longer time period, the extra calories will be stored as fat. Similarly, if you take in fewer calories than needed over a longer time period, your body will release its fat stores, and you will lose weight.
However, there is far more to weight regulation than just monitoring calories in vs. calories out. Indeed, most members of the human race appears to have regulated their weight effectively for millennia, before anyone even knew what a calorie was.
The modern obesity epidemic appears to be an unprecedented phenomenon, and it coincides with an ever-increased focus on counting calories. Correlation is not causation, so it would obviously be wrong to say that obesity is caused by counting calories. However, counting calories appears to be, at best, an imperfect aid to weight control. So what is really going on?
Hormones play a large role in influencing appetite, fullness, and fat storage. And research suggests that low-carb and keto meals may trigger hormones that lead to a natural reduction in calorie intake, especially in those who are overweight or insulin resistant.
In one study, overweight people consumed a breakfast of eggs or a bagel. Although each meal contained an identical amount of calories, the group that consumed the egg breakfast stayed full longer and ate fewer calories at lunch than the bagel group did.
Additionally, your insulin level - and how sensitive your body is to insulin - influence whether you store or burn calories. Researchers have shown that impaired insulin response following weight loss reduces metabolic rate and drives weight regain. However, lowering carb intake may help to counteract this effect.
Calories count, but you don't have to count them.
What's more, when it comes to weight loss, low-carb diets regularly outperform low-calorie diets, even in studies where the low-carb dieters are not counting their calories.In a 2004 study, overweight and obese adults consumed a low-fat diet and a low-carb diet for one week each. Both diets were designed to reduce each person's calorie intake by 500 calories per day. However, people lost more weight and body fat after the low-carb week than the low-fat week - even though the men averaged higher calorie intake during the low-carb phase.
Clearly, calories are only one factor involved in weight regulation.
Video: Doctors answer
More Q&A videos with doctorsCounting calories: yes or no?
At Diet Doctor, we don't recommend counting calories. First of all, it's impossible to know exactly how many calories you're getting from a specific food, let alone precisely what your body will do with those calories. It's far more important to choose foods that promote the release of hormones that reduce hunger, help keep you satisfied, and make it easier to achieve a healthy weight.
Focus on whole foods that contain high-quality protein, healthy fat, and nutrient-dense fibrous carbs, especially vegetables.
And if you are really struggling to lose weight, stay away from high-calorie, high-reward foods that are easy to overindulge in, even if they are low in carbohydrates. Classic examples of such foods are cheese and nuts.
Rather than counting calories, make all of your calories count by eating nourishing, well-balanced low-carb meals.-
Franziska Spritzler, RD
