Calories-in, Calories-out. Is that really all it comes down to?

Surprisingly, this concept has been the cause of much debate within the fitness industry over the years. The concept seems simple at its surface, but in all actuality it is a bit more complex than it seems. Let’s dive right on in!

At one end of the spectrum, there are those who believe that calories in, calories out (CICO) is straightforward. Meaning, weight loss is black and white. If you are not losing weight you are eating too much and moving too less. And if you are losing weight you are burning more calories than you are consuming. Sounds pretty simple, right? While this is mostly true, CICO doesn’t take into account other factors that affect energy balance or the “eat less, move more” explanation. This brings us to those on the opposite end of the spectrum and where the debate gets pretty interesting.

There are other factors outside of CICO that affect energy balance leading to weight loss or weight gain. Without getting too complicated and into the weeds, below is a pretty simple list of some factors that affect energy balance.


  • Psychological Factors
    • Sleep Quality
    • Stress
    • Self-esteem
  • Appetite
    • Hormones that control the feeling of hunger and satiety
  • Foods Consumed
    • Culture
    • Environment
    • Socioeconomic Status
    • Sleep Quality
  • Calories Absorbed
    • Age, Genetics
    • Macro nutrient breakdown/intake
    • Level of Health


  • Energy Burned Through Exercise
    • Exercise duration, frequency and intensity
    • Sleep Quality
  • Resting Metabolic Rate (Energy burned at rest)
    • Body Proportions
    • Sleep Quality
    • Age
    • Genetics
  • Non-exercise Activity Thermogenesis (NEAT)
    • Hormones
    • Stress
    • Genetics
    • Level of Health

As you can see, even though losing weight by being in a caloric deficit is the simplified truth, weight/fat loss is a bit more complicated when you take into account all other factors that go into energy balance and expenditure.

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