A while back I mentioned that I had enrolled in an introductory nutrition class. One of the perks of my job is that I get to take free night classes, and since I have been interested in nutrition for a while, I decided to take advantage of the opportunity to learn more. The class was definitely more work than I expected, but I also learned a lot! Since the diet that is most beneficial to the human body is also the diet that is best for the planet (lots of fruits, vegetables, and whole grains, unprocessed and free from pesticides), I decided to share a few things I learned that have both human and planetary health in mind.

1. I’ll start with the basics. There are two basic categories of nutrients: macronutrients and micronutrients. Macronutrients consist of carbohydrates, lipids (fats), and proteins. Micronutrients consist of vitamins and minerals. Vitamins are organic (carbon-containing), whereas minerals are inorganic.

2. Eating real food is always better than consuming supplements. In other words, it’s better to eat a healthy diet, than it is to rely on multivitamins for the micronutrients your body needs. For example, we know that spinach contains vitamins A, C, K, iron, and calcium. Instead of consuming all these vitamins and minerals in supplement form, it’s better to just eat the spinach itself. The whole food is greater than the sum of its parts.

3. Supplements can also be dangerous if you take too much. Even something good for us, like vitamins, can be harmful if we consume too many. For example, vitamin A is essential to vision, bone growth, cell division, gene expression and more. But too much vitamin A can cause blurred vision, slowed growth, and even bone loss. Fortunately, it’s extremely difficult to reach toxic levels from food alone. Most overconsumption of vitamins and minerals occurs when people take too many supplements (please see your doctor, if this is something that concerns you; I am in no way qualified to give medical advice).

4. Like with any scientific field, we don’t know everything there is to know about nutrition. In fact, we didn’t even know about omega-3s, the fatty acid that is essential to our survival, until the 1980s! Prior to that time, manufacturers unwittingly reduced the amount of omega-3 in many food products to increase their shelf life, because omega-3s can cause food to spoil quickly. Yet another reason why it’s better to eat fresh, local food, rather than food that’s been transported from across the country, or across the world.

5. Speaking of omega-3 fatty acids, they are meant to be balanced by omega-6 fatty acids, because they have opposing roles in the body. For example, omega-6s are pro-inflammatory (though they are still necessary), and omega-3s are anti-inflammatory. However, the composition of the western diet is such that we generally get far too much omega-6 and not enough omega-3. This is mainly due to the fact that we, as a population, eat a lot of meat and not a lot of plants. This imbalance at least partly explains the prevalence of heart disease, diabetes, and cancer in western cultures.

6. By the way, an “essential” nutrient is one that the body cannot make, so it must be consumed. “Essential” is not just a synonym for important (though this fact makes it important for us to consume). Maybe you already knew that, but this was news to me!

7. Most diets are based on reducing consumption of a single macronutrient (carbohydrates, lipids, or proteins). If you eliminate a food group, you will of course lose weight, but this is not a long-term solution. That’s why most people gain back the weight they lost after going on a diet (and sometimes they gain even more).

8. It’s extremely hard to maintain weight loss as an adult. This is why it’s so important for public health professionals to focus on the problem of childhood obesity, so that it doesn’t persist into adulthood. One reason for this is because of the following mind-blowing fact. Say two people weigh exactly the same. Person A has maintained that weight their entire adult life, and person B has lost a lot of weight to get to that point. Person B would have to eat far fewer calories per day than person A to maintain the same amount of weight. This is because metabolism slows down as a result of weight gain, and it seems that it might be irreversible, even if that weight is lost.

9. Diseases caused by vitamin deficiencies, such as rickets (lack of vitamin D) and beriberi (lack of thiamine) were thought to have been eradicated in the West, but still occur due to our calorie-rich and nutrient-poor diets.

10. Shaming people who are obese will not motivate them to lose weight (okay, so this something I knew intuitively before, but now I have facts to back it up). Shockingly, there are still physicians who believe this is the case, prescribing “tough love” as a form of medicine. But actually, experiencing weight shame can make you eat more, because it triggers cortisol, the stress hormone, which stimulates appetite. The fact is the obesity epidemic is not a result of a lack of motivation among individuals, but rather a cultural phenomenon in which high calorie, nutrient-poor, and over-processed foods are far easier and cheaper to buy than real, whole foods.

Did any of these facts surprise you? What have you learned recently about food or nutrition? I would love to know!