For years scientists have believed that when it comes to weight gain, all calories are created equal.

But an intriguing new study, published in the journal Nature Communications, suggests that’s not true. The body appears to react differently to calories ingested from high-fiber whole foods vs. ultra-processed junk foods.

The reason? Cheap processed foods are more quickly absorbed in your upper gastrointestinal tract, which means more calories for your body and fewer for your gut microbiome, which is located near the end of your digestive tract. But when we eat high-fiber foods, they aren’t absorbed as easily, so they make the full journey down your digestive tract to your large intestine, where the trillions of bacteria that make up your gut microbiome are waiting.

  • This is exactly how I’ve been teaching myself to approach eating in the past year. I’ve been over the weight I’d like to be for a long time, and had failed repeatedly at improving my weight or my health with lower calorie count, but ultimately nutritionally lacking food.

    Amazingly I’ve found that changing my primary goal to getting a certain amount of fiber each day and generally trying to eat nutritionally complete meals, I’ve felt better and even been losing weight more consistently. I say this with the caveat that I am soft-counting calories, but I have not been worrying about keeping track of it too much, nor have I needed to.

    It feels obvious but it’s amazing how effective simply targeting healthy foods and activities (rather than focusing on forbidding foods and activities) can work out.