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.
Here is the link to the open access article.
It’s an interesting study that many here are missing the details. It’s not a no meat diet but avoiding things like ground beef and having a steak instead. It’s not avoiding carbohydrates, but it’s replacing things like: puffed rice cereals, fruit juices, sugary drinks, American cheese, and vanilla wafers, with things that are high in resistant starch like: nuts, beans, lentils, brown rice, quinoa, etc.; and they made a distinction that things are not ground for the healthy versus unhealthy diet. This means, no nut butters or ground oat flour, etc.
The whole study hypothesis is food that is digested further in the digestive tract and can reach the intestinal bacteria is far healthier than food that is digested in the stomach and upper GI tract. What they found is far more calories are absorbed by the easy digestion food, with almost 100% of calories being absorbed. Whereas the food that doesn’t get digested until the lower GI tract have few calories absorbed by the human, more calories absorbed by bacteria, and the bacteria population grows with more healthy bacteria. These bacteria in turn produce a lot of healthy short chain fatty acids which are known healthy fats for both the vascular system and brain plasticity.
It really is a big deal because it is one of the first studies to really show that things matter and why they matter. Many experts in diet and nutrition considered something like this to be the case, but we’ve been awaiting actual evidence for this. They carried out a great preliminary study, and now we need to see if they can get the same results with a larger population.
This is interesting to me, because my intuition would be that it doesn’t matter whether the calories are going into microbiota or fat, it’s still going to end up as weight in your body (gut bacteria still add mass).
Also adding to what another person said, the difference here is high fiber vs. low fiber. And I think the discussion around nutrition in general is moving away from weight being a primary determinant of health but a symptom of health. I.E. we shouldn’t be seeking to lose weight but to eat healthily, high fiber, whole foods, less processed junk, exercise frequently, and weight is a trailing measure of our success in that.
This is interesting to me, because my intuition would be that it doesn’t matter whether the calories are going into microbiota or fat, it’s still going to end up as weight in your body (gut bacteria still add mass).
They mentioned in the article that with high fiber diets there’s more calories in the waste/scat. So you’re absorbing less into fat or the gut.
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.
I feel like the definition of processed foods is a little skewed. Like I know ground beef is technically like ground into a pulp but it is at its core just beef and likewise coldcuts can vary from mystery meat bologna to thin slices of roast beef and turky breast.
It feels like the study is less “processed” vs natural foods and more high fiber diet vs low fiber.
I wonder how drinking a fiber supplement with a meaty or starchy meal impacts digestion. Is the difference in digestion the result of calories being trapped within high fiber foods and unable to be harvested quick enough, or does the fiber run interception in the small intestine while pushing away the more calorie dense stuff.
Anecdotally, I’ve noticed this with cheap protein shakes. Even when calorie counting, I seem to gain weight with the shakes, but lose it when I cook meals myself. 🤷
I’m calory counting right now and my protein shake has around 100 kcal per portion (30g of powder) and I drink at most one per day. The effect can’t be that large, even if I go 100 kcal above my goaleI am stilleinedeficit. Except if you really drink many of those.
Tl;Dr - increasing fiber decreases the energy absorbed by the body. I haven’t had a chance to read more deeply yet.
