If there’s one thing we “know” to be true about diet and weight loss, it’s this equation, which we’ll refer to as the “Calories In/Calories Out Model:”
Weight Loss = Calories In – Calories Out
That equation has been drilled in our heads for years. Need to lose weight? Either decrease your calories in (eat less) or increase your calories out (exercise). If you “burn” 3,500 calories in total, that will translate to shedding a pound of fat. Science!
The Calories In/Calories Out Model has a firm foundation in thermodynamics. From Dr. Jules Hirsch, an obesity researcher, quoted in the NY Times:
There is an inflexible law of physics—energy taken in must exactly equal the number of calories leaving the system when fat storage is unchanged.Dr. Jules Hirsch, referenced from The Obesity Code by Dr. Jason Fung
According to this theory, weight loss all comes down to calories, right? If I just stick to the right amount of calories, I’ll be totally fine, regardless of what those calories consist of.
This begs the obvious question – is a calorie really just a calorie? In other words, are all calories created equal? One man ate 5,000 calories per day for 21 days to prove the answer is unequivocally no.
What Happens If You Eat 5,000 Calories a Day?
Sam Feltham ran a personal experiment we all dream about. He set out to test the Calories In/Calories Out Model of weight gain himself by eating 5,000 calories a day for 21 days. The only caveat: he followed a high fat, low carb diet and stuck to natural foods.
A typical day looked like this:
- Breakfast – Scrambled eggs with salmon and green beans
- Snack – Walnuts
- Lunch – Mackerel with green beans
- Snack – Pecans
- Dinner – Topside beef steak with green beans
- Snack – Almonds
He started the experiment at a bodyweight of 85.6 kg (roughly 188 lbs). If the calorie model held true, we would expect him to gain 7.3 kg (roughly 16 lbs).
What actually happened? He gained 1.3 kg (2.8 lbs) and lost inches from his waist. Yep – you heard that right. The person eating 5,000 calories a day lost inches around their waist. Sam documented the experiment on his blog, and Dr. Jason Fung broke down the results here.
Ever the dutiful self-experiment, Sam followed this test up with another. For 21 days, he consumed a similar amount of calories (5,000+) per day. This time though, the calories consisted of “cereal, bread, pasta, sugary drinks, and chocolate.”
If you had to guess, what would you imagine happened to Sam’s weight over the 21 days?
It went up! He gained 16 lbs over the 21 days. He breaks down the results on his blog here.
All Calories Are Not Equal
As you probably intuitively understand, all calories are not equal.
Carbohydrates (particularly refined, sugary ones) have a drastically different impact on your body than fats and proteins. It’s critical that we look at not just the quantity of food in the diet but also the quality of food.
Are you getting all of your calories from sodas, cereals, and breads? If so, keeping calories consistent, but swapping those foods out for eggs, avocados, and nuts will make a drastic difference.
The Calorie Model of weight loss has been drilled into our heads forever, but it neglects a few critical elements. For one, a calorie isn’t just a calorie. Depending on whether it’s coming from carbohydrate, fat, or protein, it can have a drastic impact on our body.