Many people can relate to what David Kessler, the former FDA chief, calls “conditioned hypereating” -- a drive to eat sugary, greasy processed foods that has nothing to do with hunger.

It can happen when you walk by a vending machine, drive by one of your favorite restaurants or bakeries, or even when you’re sitting at home watching TV. Suddenly you get a craving for something you know isn’t good for you -- cookies, French fries, ice cream, potato chips, that sort of thing -- and your willpower seems to crumble.

This is an epidemic problem, as in the United States 90 percent of the money Americans spend on food is for processed food, and junk food is available just about everywhere, including in hospitals and schools.

It’s clear that something about these foods is able to wield an incredibly strong force over many of us, to the point that obesity has been named the fastest growing health threat in the United States, and two-thirds of adults are already overweight or obese.

So what is going on here? What about these foods compel people to overeat them at the expense of their waistline, and more importantly their health?

Why It’s So Easy to Be Addicted to Junk Food and Fast Food

Taste, convenience and cost certainly play a role in making junk foods appealing, but there’s more to it than that. The large amounts of sugar, salt and grease in junk foods are clearly addictive.

In one study, rats fed a diet containing 25 percent sugar became anxious when the sugar was removed -- displaying symptoms similar to people going through drug withdrawals, such as chattering teeth and the shakes.

A link was found between opioids, or your brain’s 'pleasure chemicals,' and a craving for sweet, salty and fatty foods. It is thought that high-fat foods stimulate the opioids, as when researchers stimulated rats’ brains with a synthetic version of the natural opioid enkephalin, the rats ate up to six times their normal intake of fat.

Further, long-lasting changes in rats' brain chemistry, similar to those caused by morphine or heroin use, were also noted. According to researchers, this means that even simple exposure to pleasurable foods is enough to change gene expression, which suggests an addiction to the food.

Your Genes Remember When You Eat Sugar

When you eat sugar, not only do your genes turn off controls designed to protect you from heart disease and diabetes, but the impact lasts for two weeks!

Even more concerning, if you eat poorly for a long time your DNA may become permanently altered and the effects could be passed on to your children and grandchildren.

In other words, you are born with a set of genes, but the expression of those genes is not set in stone. Your genes can be either activated or silenced by various factors including your diet and even your mind. It is not your genes that dictate your future health, but rather the expression of those genes that matter.

So in the case of eating sugar, it’s now known that this switches off good genes that protect your body from disease. This is just one of many reasons why you may want to seriously limit or eliminate sugar from your diet.

Sugar is Incredibly Addictive

Another reason we know that people’s love for sugar goes far beyond taste is because of its addictive properties.

Refined sugar is far more addictive than cocaine -- it is one of the most addictive and harmful substances currently known. In fact, an astonishing 94 percent of rats who were allowed to choose between sugar, water and cocaine, chose sugar.

Even rats who were addicted to cocaine quickly switched their preference to sugar, once it was offered as a choice.

The researchers speculate that the sweet receptors (two protein receptors located on your tongue), which evolved in ancestral times when diets were very low in sugar, have not adapted to modern times’ high sugar consumption.

Therefore, the abnormally high stimulation of these receptors by our sugar-rich diets generates excessive reward signals in your brain, which have the potential to override normal self-control mechanisms, and thus lead to addiction.

Your Emotions Play a Major Role, Too

As Kessler said, "Once you know what's driving your behavior, you can put steps into place" to change it.

What this means is whenever you feel the desire to binge on junk foods, it’s necessary that you have a system in place to help curb those cravings.

The system that I personally use and most highly recommend is called the Emotional Freedom Technique (EFT). EFT is a form of psychological acupressure, based on the same energy meridians used in traditional acupuncture to treat physical and emotional ailments for over 5,000 years, but without the invasiveness of needles.

When your body's energy system is disrupted, you are more likely to experience distractions and discomforts related to food, and more likely to engage in emotional eating. Instead, if you engage your body's subtle energy system with EFT, the distracting discomforts like food cravings often subside.

The other major factor that will help you to break an addiction to junk food is tailoring your diet to your nutritional type. Nutritional Typing will teach you which foods you are designed to eat and the ideal proportions of the types of nutrients you require, whether you are a 'Carb', a 'Protein', or a 'Mixed' type.

When you eat the foods that are right for your biochemistry, it will push your body toward its ideal weight and you’ll notice that food cravings largely subside. This is because you’re giving your body the fuel it needs, so you’ll feel satiated throughout the day and be far less tempted by the sugary and greasy foods that once had a hold over you.