If you spend way too much time on nutrition social media, as I do, you might stumble upon an interesting debate: what causes weight gain and loss?
cico
The commonly-accepted view is that it’s all about calories. We take in calories when we eat. We burn some calories for energy, and store the leftovers in our fat cells. So the key to losing weight is to use more energy than we store — in a nutshell, eat less, move more.
This theory — and despite its widespread acceptance, it is still just a theory — is often called the CICO (Calorie In, Calorie Out) model, aka the EBM (Energy Balance Model). The body is an abacus, it says, and balancing the consumption and use of energy (aka calories) is what we need to do if we want to slim down. It’s a theory that has launched hundreds of calorie-counting apps and netted billions of dollars for weight-loss companies.
CICO proponents will sometimes get fancy and cite the principle from physics known as “thermodynamics,” which states that matter (in this case, food) can change forms (into energy) but cannot be created or destroyed. It has to go somewhere.
One problem with the CICO model, though, is that we don’t really burn a whole lot of calories through exercise. Check out my Apple Watch info from the other day…
I did a pretty decent Dr. Ben workout in the evening:
Insofar as my watch’s estimate is accurate (debatable, but let’s go with it), I burned a total of 320 calories during my 30 minutes at the gym. But the big picture?
Between walking, standing, sitting, sleeping, breathing, thinking, digesting, and so on, I burned a total of 3622 calories throughout the day (What can I say? I’m a big guy!). Most of this is from my Resting Metabolic Rate (RMR), the calories I burn just by staying alive. Only 926 calories are from movement.
So if we think about the calorie burn that’s actually under my conscious control (exercise and other movement), it amounted 926/3622, or about 25%. In other words, the vast majority of my “calories out,” I have no control over.
cim
On the other side of the debate is the so-called CIM, or Carbohydrate Insulin Model. This theory says that it’s all about the hormones. We eat food, which raises the amount of fuel (primarily glucose) in our blood. This signals the pancreas to produce the hormone insulin, which then shuttles that sugar out of the bloodstream and into storage (including into fat cells).
Carbohydrates — starches and sugars — raise blood sugar more than other macronutrients, which means they are uniquely fattening. Carbs also affect other hormones, such as glucagon (which regulates the use of stored glucose), leptin (the fullness hormone), ghrelin (the hunger hormone), and more.
Food is information, the CIM says, and the makeup of our diet sends signals to the body that tell it what to do. This means that what we eat is more important than how much we eat.
A critique of the CIM is that it would seem to imply that you can eat butter and bacon all day, and never gain an ounce. But in real life, this isn’t true. Even Dr. Ben Bocchicho, a big proponent of controlling your carbs, once told me, “I can eat plain roasted chicken thighs for dinner, but if I eat twenty of them, I’m not going to lose weight.”
going to mass
A few weekends ago, I tuned into the SMHP conference online. Dr. Michael Eades, author of the 1997 book Protein Power, one of the OG Low Carbers from way back in the day (and a fellow Substack author), gave a thoughtful talk on CICO and CIM called “Weight Loss: Calories, Insulin or a Third Alternative?”
Eades says that CIM has the advantage of being a model that can at least be tested, because it posits a mechanism for weight gain or loss — namely, hormonal changes. CICO does not. Proponents of CICO “go to great lengths to try to show causality, (citing causes like the availability of cheap, ubiquitous, highly processed food) but it really isn’t there.”
Eades then outlines what he calls “The busy restaurant question”:
“Let’s say you go to a restaurant that you frequent, and it’s normally not very crowded. But all of a sudden you go one night, and there are a million people there — they’re belly to belly and back to back.
You go up to the maitre’d and you say, ‘Why is it so crowded tonight?’ and he says, ‘Oh, that’s because there are more people coming in than there are leaving.’
You’d say, ‘Are you a moron? That doesn’t tell me anything. Why are there more people? Did a baseball game just let out? Did a Broadway show just finish?’
That’s what the Energy Balance Model is. It tells what’s happening, but not why.”
Eades goes on to ask a very provocative question: what if, by focusing on calories, we’re barking up the wrong tree? In truth, the law of thermodynamics should say that change in weight (aka, mass) is a matter of mass in versus mass out. Perhaps we should be focusing on the amount of food, not the calorie content.
We take in mass through food, water, and oxygen. We get rid of mass through respiration, perspiration, bathroom activities and so on. Perhaps, he says, low-carb diets work because fats are more calorically dense than carbohydrates. This would mean that a 2500-calorie/day diet high in fats has less total mass than a diet of the same number of calories from carbs.
You could almost hear the minds blowing all over the room.
Eads’s so-called “mass balance equation” is a really interesting idea. He admits that it’s just an idea at this point — untested, but one that might be worth looking into. It’s certainly a huge paradigm shift, and one that I’m still trying to get my head around.
back to ozempic
A few weeks ago, I waded into the discussion about weight loss drugs — the pluses, the minuses, and the still-unknowns. One thing that we do know, for a scientific fact, is that they work. They do lead to weight loss. What’s interesting to me. though, is the possibility that they can also point us toward resolving the CICO-CIM debate.
People who take Ozempic, Wegovy and other semaglutides eat a lot less. Fewer calories in → weight loss. Score one for CICO.
To put a finer point on it, these folks eat less total food, by volume. Less mass → weight loss. Score one for the Mass Balance Equation
But why do they eat a lot less? Because their brains are being flooded with synthetic hormones at five times any level found in nature. High GLP1 → decreased hunger → less food → weight loss. Score one for CIM — or at least its underlying focus on the importance of hormones.
In Eades’s terms, these drugs shed some light on both the what and the why. And in the long run, this might be the real breakthrough that comes of these so-called “breakthrough drugs.” Time will tell.