Beyond Calories – Sun 5.20.18
This article, Beyond Calories, is from the CrossFit Journal:
In fall 2017, I spent 45 minutes speaking to CrossFit Inc.’s Seminar Staff about the nutrition lecture in the Level 1 Certificate Course. The original intent was to help staff lecturers develop a deeper understanding of the material.
As an example, I used our stance on the “calories in versus calories out” model. The traditional approach—“take in less than you expend”—is not sufficient to account for current levels of obesity and chronic disease. A short clip of from this lecture was posted to Instagram, and many viewers didn’t quite understand my main critique. This article should help the reader understand the main problem with the calories in/calories out approach to explaining metabolic dysfunction.
Energy Balance: An Oversimplification
It is widely accepted and proven that obese people take in more calories than they expend. It’s not that calories in/calories out needs to be completely discounted, but the energy-balance equation, as it is called, is an oversimplified approach that does not explain the chronic-disease epidemic.
Centers for Disease Control figures from 2014 show that 36.5 percent of Americans over 20 are obese, yet I do not believe they are just gluttonous and lazy. So why is the epidemic getting worse? The answer to this question can help us develop a solution. Essentially, the body and the brain do not treat all calories the same.
First, let’s talk about how the brain treats calories differently. This gives some insight into why we eat more than we need—hedonic eating (overeating) as opposed to homeostatic eating (eating to meet energy needs). Before food was readily available—especially processed food—humans had to hunt and gather food to stay alive. Over tens of thousands of years, our brains evolved to prioritize foods that offer the greatest chance for survival: readily accessible, palatable foods that provide high amounts of micro- and macronutrients. The brain prioritized these highly palatable sweet and savory (umami) foods in order for the species to survive.
Prioritization happens within the reward system of the brain. The mesolimbic, or reward, pathway is made up of the nucleus accumbens (NA) and ventral tegmental area (VTA). Dopamine plays a major role within this system. The VTA is a site of dopaminergic neurons, and this area tells us whether an activity is rewarding or not (food, sex, recreational drugs, etc.). The amygdala also plays a role. It puts values on experiences. If an experience is rewarding or aversive, it is ranked among other rewarding or aversive experiences. Ranking is an important factor in survival. Fleeing a predator should obviously rank higher than sex or food. Finally, the hypothalamus plays a major role in hunger and satiety. It interacts with two main hormones, ghrelin and leptin. Ghrelin is mainly produced in the stomach and is a driver of hunger and food intake. Leptin is produced in the adipose tissue, or fat cells, and suppresses appetite.
Your brain prioritizes food differently. Our ancestors had to hunt and gather food to survive. When they were able to kill a plump animal or find a tree covered in fruit, they ate and received a high dose of dopamine. This created a reward ranked among other rewards. Availability and ease of access probably played a large role in how each reward was ranked. The foods highest on the list were likely palatable, calorically dense and readily available. As you can see, all calories are not treated equally by the brain.
Over time, brains adapted to this ranking system, and our ancestors sought out high-ranking foods, with sweet and savory tastes preferred. Foods high in sugar and fat, such as fruit and animal meat, generated a dopamine response. This release of dopamine created a drive to seek out more of the same food. Meat and fruits are also high in fiber and protein. Because fiber and protein have effects on satiety, some amount of quantity control might have been associated with the highly rewarding foods our ancestors craved. Either way, overeating sugar and fat was impossible when fruit was not plentiful and high-fat animals were hard to find and kill.
All this worked in practice: Eat as much as you can and store it because you never know when such an opportunity will present itself again. Consuming food in this manner and storing energy would increase leptin, signaling the hypothalamus that enough energy is present within the body. Food intake could then be lowered and energy expenditure increased.
Fast-forward to the present, when the food environment has evolved but that part of our brains has not. Food is readily accessible, and much of it is processed, making selections calorically dense and highly palatable. This is a recipe for disaster.
If you want a snack, do you eat a cookie or an apple? The cookie is high in processed sugar and processed fat, and it’s low in fiber and protein. It’s also extremely tasty. The cookie creates high levels of dopamine and is assigned a high reward value by the brain. Higher reward values mean items will become most likely to be picked again. High levels of dopamine and lowered inhibition also cause us to eat past fullness.
When you see a cookie, you’re drawn to it even though you know it isn’t good for you. Why don’t you eat just one? Dopamine is high and inhibition is low. The signals tell you to keep eating. Minimal fiber and protein are present: keep eating. The cookie is super sweet and highly palatable: keep eating.
Manufacturers know how we behave and have even played on our behavior to market products: “Betcha can’t eat just one.”
Rewarding foods condition people to eat more. This is why 36.5 percent of America’s adult population have failed to consume fewer calories than they expend: They are eating foods that kidnap their willpower and tell them they need more, not less.
Try telling someone to eat less and work out more when he or she is eating highly processed foods. It won’t happen. In essence, these foods become addictive. Companies put a lot of effort, money and time into finding the optimal mix of sweet, salty and savory to keep you eating and coming back for more, further increasing their bank accounts and diminishing your health.
As you can see, the type of food plays a role in one’s success or failure in the calories in/calories out model. It’s not simply the number of calories.
Biology and Bad Food
The reward system does a great job explaining why we overeat processed foods, but that’s only half the issue. Now let’s look at how processed food is making us sick.
These foods are readily available, addictive and sugar laden. The sugar in these foods is mostly likely sucrose or high-fructose corn syrup (HFCS). Sucrose is 50 percent fructose and 50 percent glucose, and HFCS is approximately 55 percent fructose and 45 percent glucose.
When we eat glucose, the pancreas produces insulin. Approximately 20 percent of the ingested glucose goes to the liver, where insulin signaling drives the conversion of glucose into its storage molecule, glycogen. The other 80 percent goes into the bloodstream. Increases in blood glucose cause the pancreas to produce insulin, which signals tissues and organs such as skeletal muscle, adipose structures, the brain and the kidneys to take up the glucose, lowering levels of blood glucose. Insulin stimulates GLUT4 proteins (receptors) on cells to transport the glucose inside, to be used or stored as glycogen or fat.
Fructose has a completely different fate: It goes straight to the liver, which is the primary organ that metabolizes it. When fructose comes from a natural source such as a piece of fruit, fiber is present. Fiber helps us feel full faster, and it slows down absorption from the intestine, thereby decreasing the rate at which fructose reaches the liver. This allows the mitochondria to keep up. When fructose comes from a highly processed food source, it is missing fiber, so it enters the liver at an accelerated rate and the mitochondria cannot metabolize it fast enough.
This overload results in de novo lipogenesis, or fat accumulation around the liver. As it accumulates fat, the liver produces VLDL and LDL (triglyceride-enriched particles) that are sent into the bloodstream, leading to hypertriglyceridemia. As fat continues to accumulate around the liver, the liver becomes insulin resistant, which has downstream effects such as peripheral insulin resistance, CNS insulin resistance and Type 2 diabetes.
When the liver is dysfunctional, it activates carbohydrate-responsive element-binding protein, which continues to stimulate hepatic glucose production. This continuous increase in blood glucose and insulin potentially causes the downstream effects in the CNS and periphery.
When a person is insulin resistant, his or her GLUT4 proteins (receptors) no longer hear the insulin signal, which leads to chronically high levels of insulin in the blood. Insulin can override leptin signaling, and if the brain is no longer receiving leptin’s signals, it thinks the body is hungry and needs calories. You can think of this as a “false sense of starvation.” It is false because food is actually coming in but it is the wrong type of food—it is processed food and further compounds the problem. The brain thinks the body is starving, so it seeks out more food (prioritizing easily accessible, palatable food that’s high in calories) and lowers energy expenditure (if no food is coming in, let’s conserve).
The equation: more processed food coming in + less energy going out = sick.
The Easy Fix
In the end, energy balance is an important part of the issue but not a complete explanation of the problem. It doesn’t explain why people consistently eat more processed food and move around less. You simply cannot expect someone to eat less and move around more when he or she is eating in such a way that the body, brain and physiology are fighting against the person.
This is only part of the problem. Chronic disease and obesity are very complex and more involved than the discussion above. Though the problem is complex, the solution is simple: Don’t provide your brain with palatable, easily available, calorically dense, addictive foods. Reduce your intake of processed foods and you will reduce the amount of sucrose (and, therefore, fructose) that you consume. Change your food environment. Eat meats and vegetables, nuts and seeds, some fruit, little starch, and no sugar. If you do, the simple energy balance can help you maximize results. If you are already eating natural foods that work well for you, keep your intake to levels that support exercise and not body fat.
Essentially, eat quality foods and only eat enough to support your activity.
The solution is simple.
About the Author: Michael Giardina, CF-L4, has been on CrossFIt Training’s staff for 10 years and now serves as a FlowMaster and Content Supervisor. He holds a master’s degree in applied exercise and health science from Kennesaw State University, and he is currently working on a master’s degree in public health (epidemiology and biostatistics) at the University of Southern California.