In short, NO.

One of our members asked a great question in our facebook group yesterday ;

Is Eating a thousand calories of so called junk food vs eating a thousand calories of single ingredient food the same? Would you get the same energy and results?

Solv CF Member

In other words if I eat the same amount of calories of junk food as I do whole food would I receive the same level of energy measured by calories and results?

So I got investigating. First of all I should reference where my information is from and my biases. I’m a student of Precision Nutrition, who claim to be the worlds #1 rated Nutrition Certification company. They previously had ties with CrossFit and are still a chosen preferred course of study for CrossFit trainers around the world.

When a calorie isn’t a calorie: Thermal effect of food

Everyone usually knows that calories are a measure of energy. Weight change depends on the balance between two things: energy in versus energy out, ‘the energy balance equation.’

Energy out includes obvious things like:

  • Exercise or daily physical activity (activity metabolism)
  • energy to keep you alive at rest (basal metabolic rate)
  • energy added to the body like amino acids to muscle, and fat to fat tissues

And less obvious things like:

  • energy lost in waste (feces and urine)
  • energy used to digest the foods that you eat

Energy in seems simple: How many calories were in the spinach salad, bagel or ice cream sandwich you ate?


Turns out, energy in is just as complex as energy out, because of the energy cost of digesting food. Digesting food actually cost’s us energy.

But how much energy? Do different types of foods cost us different amounts of energy? Do some foods require more digestion than others?


Have you ever wondered why celery has a negative calorie measurement? Because it takes more energy for you to break down and absorb than the celery contains.

Eating costs calories: calories to chew, swallow, churn the stomach, make the acid in the stomach, make the enzymes, to make the rhythmic muscular contractions known as peristalsis that drive the food through, and so forth.

Scientists have three names for this phenomenon:

  1. dietary-induced thermogenesis (DIT);
  2. thermal effect of food (TEF); or
  3. specific dynamic action (SDA).

On average, a person uses about 10% of their daily energy expenditure digesting and absorbing food, but this percentage changes depending on the type of food you eat. Protein takes the most energy to digest in fact, 20-30% of total calories in protein eaten go to digesting it. Next is carbohydrates which is estimated between 5-10% and then fats at 0-3%.

Let’s say you eat 100 calories worth of protein, your body uses 20-30 of those calories to digest and absorb the protein. You’d be left with a net of 70-80 calories. Pure carbohydrate would leave you with a net 90-95 calories, and fat would give you a net 97-100 calories.

And this is where we start to see that “a calorie is just a calorie” might not be all that helpful.

Back to Matt’s question for a moment, are calories consumed from junk food the same as calories consumed from whole food or single ingredient foods?

A study was conducted in 2010 to find the differences in energy expenditure between a whole food diet and a processed diet. I’ve linked the study here along with the conclusion for you to read yourself but I’ll summarise their findings here.

The study compared what happened when 17 volunteers ate a whole food meal versus a processed food meal. Volunteers were all of normal weight, and about 25 years old.

The researchers use the term meals rather loosely, since these meals were cheese sandwiches. In this study, the metabolic impact of whole food sandwiches made of multi-grain bread and real cheddar cheese were compared to processed food sandwiches that were made with white bread and processed cheese product.

Though the researches call the sandwiches whole food and processed food,both are processed, but just to a different degree.

They found that overall, processed food or junk food takes less energy to digest and absorb when compared to whole foods. So 100 calories of processed food ends up being more net calories than 100 calories of whole food. So if you’re trying to lose weight, whole foods are a better option as you can more likely eat more volume of food whilst remaining in a calorie deficit, something our 28 day nutrition challengers have just started yesterday. If you’re trying to gain weight, you may find that you need to include a little more processed food for a while.

The students who participated in the study said they felt no differences in how energetic they felt after eating the two sandwiches. And they felt no differences in fullness even though the study found that eating whole foods took a whopping 46.8% more energy to digest on average than processed food!

This confirms a lot to me as a nutrition coach. It’s easy for us to think we are not eating a lot and yet still see the scales go up and that’s because of two things, 1. We are not aware of the amount of calories in our food and 2. We are not eating enough of the foods that would make us feel energised such as fruits and vegetables. As we said earlier, a cheese sandwich of any description is processed, in the study one was just more processed than the other. If you want to feel energetic from food you need to be eating a lot of fruit and vegetables daily.

So there you have it, not all calories are equal, you will get different results and feelings from eating different quantities and calories of different foods. Experiment for yourself, track you progress and determine your own results from learning more about food.

Before you go here is some bonus content for you.

What is truly “whole” food?

When judging what’s “whole” and “processed” foods, ask yourself the following:

  • What’s on the ingredient list?
  • Do I recognize all these things?
  • How many steps did this food take to get to me?
  • Does this food come in a bag, box, or can?

For a real eye-opener, next time you’re at the supermarket, take a look at the ingredients of a few different brands of yogurt and compare the ingredients. Good quality plain yogurt will have two ingredients: milk and bacteria. Other so-called yogurts will have things like sodium citrate, corn starch, gelatin, pectin, calcium phosphate, potassium phosphate and sodium phosphate.

By the way, you might also be surprised to see what is in cream. Yep, plain old cream is often actually milk with cheap emulsifiers and sweeteners such as dextrose.

I hope this helped!

All resources and articles are from


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