For example, vegetables are generally healthier than meat because they contain more nutrients, less fats e.t.c. Why do certain food categories have properties that make them healthier than others?
In: Biology
Your body needs two things from your food. Energy and nutrition (vitamins, minerals etc.), you can think of nutrition as building blocks for your body. Stuff your body needs to grow, heal or run the many chemical processes in your body that make life possible. If there’s anything in your food that doesn’t fall into those categories, it simply isn’t processed and discarded as waste.
Unhealthy can come in many forms. Excess energy is a simple one. Running your body requires energy. You need to generate body heat, your muscles need energy to move and so on. But if you take in significantly more energy through your food than you expend, the excess is stored as fat. Which means you grow fat with all the associated health issues.
We express that energy in terms of calories. Sugary or fatty foods like candy, chips, pastries etc. are high in calories and low in nutrition so they’ll quickly turn you fat if you don’t exercise a lot to burn off the excess energy.
And that brings us to the next example of unhealthy eating. Empty calories. When you eat foods that have a high caloric content but a low nutritional content, you’re eating empty calories. You’re providing your body with tons of energy but almost no nutrition. Remember, nutrition is all of the things that are essential to the proper running of your body. It’s like providing your car with gasoline but not coolant, oil, air in the tires etc. ie. it’ll have the energy to move but miss the essentials to do so without slowly breaking down.
And now for a more subtle example. Sugar is very easy for your body to absorb. If you eat a piece of chocolate, your body won’t have to break it down with acid and slowly absorb it’s nutrients while it passes through your digestive system. The sugar is just almost 100% absorbed right away, minutes after eating it.
This gives you an immediate and enormous energy boost that crashes down just as fast because you absorb all of the energy right away and then there’s nothing left.
By comparison, if you eat some green beans, you’re eating a complex food item with a fair amount of indigestible fibre. That means your body has to work hard to digest it and the green bean’s energy is released slowly over time. Providing you with a much more balanced supply without any highs and crashes.
So to make it a little more practical. Unprocessed foods like meat, fish, vegetables, nuts and fruits are nutritionally complex. These are the products of living things that needed many different nutrients in their own right to grow. A vegetable that absorbs many nutrients from the soil to fuel it’s own growth will often have equally nutritionally complex tissues for us to eat.
By comparison, processed foods like noodles, chips, sauces, candies etc. are purpose made. And that purpose is usually not to provide us with nutrition. A lot of snacks are very salty, fatty and sugary because those elements are addictive to us (in the wild extra energy is precious instead of a health hazard). Food items like noodles are meant to be filling (lots of carbs) but they’re not made to supply you with vitamins for instance.
Eating processed foods too often amounts to eating those empty calories we mentioned. It’ll fill you up and likely fatten you up. While at the same time depriving you of all that nutrition you need so badly.
That’s why at the end of the day, a healthy diet comes down to limiting your caloric intake while making sure you meet your nutritional goals. And that usually requires you to eat a good amount of vegetables and protein sources while limiting sources of fat and sugar.
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