Unbeknownst to many people, the foods we buy have toxic additives lurking in them. This means they've been altered in ways that actually make you hungrier and hijack the brain to worsen your emotional eating habits.

As a Harvard-trained nutritionist, I always remind people to read the food labels. Of course, you don't have to avoid certain additives completely. But moderation can do your body a whole world of good.

Watch out for these toxic food additives

1. Monosodium glutamate (MSG)

Added to many flavored foods, MSG antagonizes your pancreas into pouring out more insulin — a hormonal cascade that makes you feel hungrier.

MSG has been linked to diabetes and obesity, and is even considered an excitotoxin, which can cause brain cells to get overexcited and then fire uncontrollably, potentially leading to cell death.

2. Refined flour

The word "refined" in flour refers to a modification process in which the bran and germ are removed, allowing products to stay on the shelves longer. But it also removes the naturally occurring vitamins, minerals and dietary fiber.

Refiner flour, mainly white flour, jacks up your blood sugar levels fast, spiking your insulin levels and then making them crash.

This reaction makes you hungry very quickly, which explains why you may feel like eating again soon after having a bagel or a slice of toast.

3. Refined sugar

White sugar works on the body in a very similar way to refined flour. It sends your blood sugar sky-high and then makes it crash a short time later, intensifying your craving for sugar.

Once you start eating it, it can be difficult to stop. Sugar can make you briefly feel high (as in "on a drug"), and creates a spark of energy in your body because of the dopamine release it brings.

A particularly vile form of refined sugar is high fructose corn syrup. Laced in sodas, commercial juices, and other beverages as well as packaged foods, it messes up your normal metabolism.

Studies have found that this additive slows down the release of leptin, or the "I'm full" hormone.

4. Gluten

Back to white bread: Another reason it makes you hungry is its gluten content. Gluten is a protein in wheat that is often present in processed foods.

It can be highly inflammatory in certain groups of people because of its sugar-like properties when refined, and it is also a gut irritant.

A good rule of thumb is to avoid gluten-containing products for a month. See how you feel and note whether you are in better control of your cravings.

Personally, gluten was a hidden food sensitivity for me, and I do better without it. Because of the decreased nutritional value in most grains, they should be only a small part of our diets anyway.

Instead, make polyphenols your best friend

Polyphenols are a type of micronutrient that contain health-promoting properties. They are important for clearing our bloodstreams and toxins, and are key to controlling hunger and cravings for unhealthy additive-filled foods.

Here are some of my favorite foods that are high in polyphenol:

• Avocados
• Berries
• Broccoli
• Cherries
• Chili peppers
• Citrus fruits
• Coffee
• Flaxseeds
• Dark chocolate
• Garlic
• Legumes
• Mangoes
• Nuts
• Olives
• Onions
• Oregano, as well as many other herbs and spices (choose organic if you can in order to avoid pesticide residue)
• Pumpkin
• Spinach
• Green tea

Polyphenols can reduce and control your blood sugar levels, too. So if you want to change your diet and eat more nutritiously, increasing your intake of them is an excellent way to start.

Dr. Amy Shah, MD, is a double board-certified medical doctor and nutritionist specializing in food allergies, hormones and gut health, with training from Cornell, Columbia and Harvard. She is also the author of "I'm So Effing Hungry: Why We Crave What We Crave, and What to Do About It." Follow her on Instagram.

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