why processed food kills your waistline and mood, and how fresh food can save both

One of the recurring topics here over the last few weeks is that lifestyle studies and fitness and diet advice aren’t always as definitive as the news makes them sound, especially when there seem to be so many contrarian data points and conclusions. But one of the constants in much of the research into obesity and diets is that highly processed food is associated with weight gain, certain cancers, and chronic conditions from rapidly expanding bellies. Even as it’s adding fewer flavorings, preservatives, salt, and fat, read-to-eat far in grocery stores is still just as problematic as it always was, which made researchers wonder why it’s so bad for you past its nutritional content and set up an experiment in which nutrient, calorie, and flavoring-identical fresh foods were pitted against highly processed ones.

Unlike many similar studies, which rely on reviewing records from tens of thousands of people and try to correct for variations in their behaviors with statistical formulas, this one focused on 20 paid test subjects who were kept in isolation for a month and ate only what they were given with no excursions or room for improvisation in their meals. The only twist is that they could eat until they felt full instead of a precise serving amount to test the researchers’ hypothesis that our bodies deal with highly processed foods differently. What happened? Those who are highly processed meals consumed roughly 500 calories more per day to feel equally satiated, even though they ranked both the processed and freshly made food as equally tasty. That can add up to a lot of extra weight over the years, and in turn, a lot of chronic problems.

how does processed food defeat portion control?

So, what does this study tells us? Well, it confirms that a calorie is not a calorie is not a calorie, and how the food is prepared and consumed matters over the long term. The processed food might appear to be a smaller portion, it may go down easier so we eat it faster, it may be more flavor dense so we get distracted and lose track of how much we eat, or there may be some combination of all these things and more, but the end result is that we just plain eat too much of it when it’s on our plates. Our smartphones might be able to scan a food and know exactly how many calories it’s reported to have and the right size for a serving, but our eyes, mouths, and stomachs can’t, going by general taste, feel, and visual reference. Ultra-processed food just plain confuses us about what a healthy portion is, and we pay for it in the end.

Even worse, if that processed food has too much fat added to it to maintain flavor after weeks or months in the freezer, the fatty acids deposit themselves in the brain and mess with a neural pathway associated with depression, according to a study in mice. After being fed a fatty diet, they exhibited both the physical and chemical signs of depression and lethargy no matter how much or little weight they gained. The culprit, it seems, is a protein called kinase A (PKA), which messes with the hypothalamus if something interferes with its normal signaling patterns. When we combine the findings of the two studies, we get the following grim picture. When we feel sad, stressed, or depressed, we turn to highly processed, fatty comfort foods, or rely on them to save time on cooking. We eat too much of them because it’s hard to feel satiated with what should be a healthy portion, and fatty acids mess with our brains, causing us to feel depressed in a vicious cycle while we get heavier and sicker.

but wait, it gets worse. much worse…

With more bulk and depression symptoms, we have less incentive to exercise, more stresses us out, turning us to more processed food. And even though it can be just as nutritious as freshly cooked, minimally processed items, we end up craving more of it, gaining even more bulk. The added mass means we have more cells, and more cells means more chances for some form of cancer to develop, especially as weight gain suppresses the immune system which is necessary to keep would-be cancers in check, and disrupts the flow of hormones, which can allow more expressions of deleterious genes or disrupt the regulation of cell growth, increasing the attack surface for cancerous cells and lowering our defenses against them.

In short, it’s not exactly accurate to say that weight gain from highly processed foods or that processed foods cause cancer, it’s that they make us more susceptible to cancers and other issues created by all the aforementioned negative changes in our bodies. What we can say is that armed with the data from these experiments, we can see why cutting out processed foods helps weight loss, or just the conversion of fat to muscle and huge improvements in mood and libido. This also hints that maybe our advice to those struggling to lose weight should be just to try and get more exercise, eat less, and count calories, but to cut out fat while making cooking and exercise hobbies, as well as focusing not on the scale, but on how they feel, how they look in the mirror, and how their clothes fit.

See: Hall, D., et. al., (2019) Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake, Cell Metabolism, DOI: doi.org/10.1016/j.cmet.2019.05.008

Vagena, E., et. al., (2019) A high-fat diet promotes depression-like behavior in mice by suppressing hypothalamic PKA signaling, Translational Psychiatry (9) No. 141, DOI: 10.1038/s41398-019-0470-1