Here's How Proteins and Carbs Change When They're Cooked

The way you cook protein and carbohydrates changes their textures and flavors, as well as their nutrient profile.
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When it comes to the basics of a healthy diet, protein and carbohydrates are probably the top macronutrients on your mind. They supply you with energy while stabilizing your blood sugar levels and keeping you full.

But you might be wondering how cooking process changes their nutrient content and the textures and tastes of the food.

For starters, cooking can do two opposite things: either reduce the concentration of phytochemicals or increase the extractability of phytochemicals, resulting in a higher concentration, according to a November 2013 review in the Journal of the Science of Food and Agriculture.

What's more, different cooking techniques give you different flavors through their processes. "Grilling adds some char and smoke, while braising gives you an extra flavor depending on the type of braising liquid you are using," Craig Emmons, a chef at Freshly, tells LIVESTRONG.com.

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What You Need to Know About Cooked Protein

Protein is made up of amino acids — some of which your body makes on its own — but there is another group called essential amino acids, which you get from food. Some foods contian all nine essential amino acids and are known as complete proteins.

To get a complete amino acid profile in your diet, you'll want to vary your protein sources. From chicken and fish to dairy, eggs, beans and grass-fed meat, there are many delicious ways to get enough protein in your diet. What's great about protein is that it's so versatile, so it lends itself to different cooking techniques.

"When cooking protein at high temperatures, such as searing, you create a barrier on the outside of the protein that helps lock in existing moisture. Because it is a faster method of cooking, you may not get a protein to be as soft as you want," Emmons says.

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But when you cook protein at a lower temperature, such as smoking, it can yield meat that's not as tough. "Smoking is is a great example of low heat. The phrase 'slow and low' allows someone to impart a lot of flavor into a protein while controlling moisture content as well as the texture," Emmons says.

Emmon also recommends stir-frying and sauteeing your protein and veggies. "With stir-frying and sauteing, you can get a great flavor out of vegetables and proteins by using high heat and low fat. This involves working faster and being more prepared, but these methods can produce great texture and flavor when properly utilized," he says.

HCAs and PAHs from Cooking Protein

However, when you're cooking protein, you want to be wary of how some cooking techniques can form hetereocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs).

These chemicals are formed when meat muscle in beef, pork, fish and poultry are cooked at high temperatures, such as pan-frying and grilling directly over an open flame.

HCAs are formed when amino acids, sugars and creatine or creatinine react at high temperatures. On the other hand, PAHs form when fat and juices from grilled meat drip onto the surface or fire, according to the National Cancer Institute (NCI).

This causes flames and smoke, which can adhere to the surface of the meat. Cooking methods that directly expose meat to an open flame or a hot metal surface contribute to PAH formation.

Studies have linked HCAs and PAHs to different types of cancer, including breast cancer. According to a January 2017 study in the Journal of the National Cancer Institute, which included more 1,500 women diagnosed with primary invasive or in situ breast cancer, high intakes of grilled, barbecued and smoked meats before diagnosis was associated with an increased risk of death.

Moreover, among women who continued to eat high amounts of grilled, barbecued and smoked meat after diagnosis, the risk of all-cause death was observed to increase by 31 percent.

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How to Reduce Your Risks of HCAs and PAHs

To help reduce HCA and PAH formations in your food, the NCI recommends avoiding cooking meat for long periods of time under high temperatures.

The NCI also advises turning meat over high heat frequently as opposed to leaving the meat on the heated surface without flipping it often. You can also pre-cook the meat and finish cooking it on the grill.

Moreover, marinating your meat, particularly with beer marinades, can inhibit the formation of PAHs in your food, a March 2014 study in the Journal of Agricultural and Food Chemistry suggests.

Using antioxidant-rich marinades made with beer, herbs and spices can help reduce the formation of HCAs, according to another June 2012 study in the Journal of Agricultural and Food Chemistry.

What Happens When You Cook Carbs?

Carbohydrates are primarily found in foods with grains, sugars and fiber. Simple carbs are foods made with sugars, like fruit sugar or table sugar. Some examples are white bread, white pasta and baked goods.

Complex carbs, however, contain three or more linked sugars and supply more nutrients. Whole grains, beans, sweet potatoes and whole-wheat pasta. Because complex carbs have longer chains of sugar molecules, they take longer to digest, stabilize your blood sugar and can keep you fuller than simple carbs.

Caramelization

When carbohydrates are cooked, their sugars caramelize. You'll notice that bread turns golden brown on the top as a result of caramelization. But fruits and vegetables can be caramelized as well.

"Grilling fruits and vegetables allow the sugars in them to heat at a rapid rate and achieve a quick caramelization without breaking it down and maintaining texture. Baking allows you to have a slower, more controlled caramelization while also managing texture," Emmons says.

Much like meat, you don't have to swear off grilling vegetables and fruits to avoid HCAs and PAHs. By simply reducing the amount of time you grill vegetables and fruits and seasoning them with herbs, like rosemary, thyme and parsley, you can minimize your exposure to HCAs and PAHs.

Gelatinization

Another process that carbs go through when cooking is something called gelatinization. "Gelatinization is the process of breaking down the intermolecular bonds of starch molecules in the presence of water and heat," Emmons explains.

This allows water to enter spaces of the starch, which creates new texture and composition. "It's a lot like pulling apart a cinnamon roll or unwrapping a present," he says.

This chemical change is used to make cooked sauces, breads and other baked goods. When you add certain carbohydrates, such as flour, to liquids, the heat gelatinizes the carbohydrates. This is the process used to make gravy and other thick sauces.

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