Food addictions are not strictly "psychological" problems, but have a hard-wired, organic component. Many of the most commonly consumed foods in Western culture actually contain narcotic properties associated with the presence of psychoactive chemicals that bind to opioid receptors in the nervous system. These peptides are so powerful that researchers block their action with drugs such as naltrexone which is used to treat addiction among heroin abusers, and naloxone which is used to prevent death from heroin overdose.
These "food opiates" are heavily concentrated in wheat and dairy products, especially cow’s milk. Wheat contains the following opioid peptides, known as gluten exorphins, alongside which are listed their amino acid structure:
- Gluten exorphin A5: H-Gly-Tyr-Tyr-Pro-Thr-OH
- Gluten exorphin B4: H-Tyr-Gly-Gly-Trp-OH
- Gluten exorphin B5: H-Tyr-Gly-Gly-Trp-Leu-OH
- Gluten exorphin C: H-Tyr-Pro-Ile-Ser-Leu-OH
- Gliadorphin: Tyr-Pro-Gln-Pro-Gln-Pro-Phe
- β-casomorphin 1-3: H-Tyr-Pro-Phe-OH
- Bovine β-casomorphin 1-4: H-Tyr-Pro-Phe-Pro-OH
- Bovine β-casomorphin 1-4, amide: H-Tyr-Pro-Phe-Pro-NH2
- Bovine β-casomorphin 5: H-Tyr-Pro-Phe-Pro-Gly-OH
- Bovine β-casomorphin 7: H-Tyr-Pro-Phe-Pro-Gly-Pro-Ile-OH
- Bovine β-casomorphin 8: H-Tyr-Pro-Phe-Pro-Gly-Pro-Ile-Pro-OH
It can be argued that many of the most popular foods consumed in Western culture are done so not primarily for their nutritive value but rather for their addictive properties. Some of these foods we become truly infatuated with and are identified as "comfort foods," that are "to die for," or that we "love."
Food opiates are widely distributed throughout our diet, and are found in many unsuspecting places. Fructose, which is fast becoming the primary source of calories in the American diet, while not itself an opioid peptide, is known to increase brain levels of endogenous morphine following ingestion,and may produce metabolic products in the brain very similar to those produced by morphine. In fact, it has been identified to stimulate a "hedonic pathway" in the brain, not unlike alcohol, which incidentally is metabolized along the same liver pathways. Fructose, in isolated or concentrated form, is highly toxic and have been linked to over 70 health conditions.
Some other common food opiates include
- Spinach: popular leafy green contains two opioid peptides named rubiscolins-5 and -6.
- Coffee: the oil known as cafestrol which is found in both decaffeinated and caffeinated coffee contains potent morphine-like activity. Many of coffee’s effects therefore may be mediated via opiate receptors, as well as the effects of caffeine. 
- Rice protein: rice albumin may have opioid properties, depending on how thoroughly it is digested; incomplete digestion may increase the likelihood of there being a pharmacologically active effect.
- Meat and Fish Protein: when complex animal proteins are enzymatically degraded some exhibit opiate-like properties. Some of these "biogenic peptides" as they are known have been investigated for their potential role in the treatment and prevention of hypertension.
- Chocolate: One of the well-known mechanisms behind cocoa’s cardioprotective activity is the ability of epicatechin to act via opioid receptors, specifically through the δ-opioid receptor, to produce cardiac protection from injury associated with low oxygen. Animal feeding studies also show that the opiate-blocking drug naloxone reduces chocolate cravings, suggesting that some of chocolate’s desirable qualities may be related to their opiate activity in the nervous system.
- Sugar: As mentioned above fructose has opiate-like properties, but so does sucrose (table sugar) and glucose. Since starch as found in "complex carbohydrates" is hidden sugar and often technically higher on the glycemic index than actual sugar (e.g. puffed rice makes the blood sweeter than white sugar), even grains may elicit addictive behaviors through the modulation of opioid pathways in the brain.
While many of our most commonly consumed foods and beverages contain food opiates, our original infatuation with opiate peptides actually begins at birth, as is nature’s inherently intelligent design. Being born into the world an extremely underdeveloped mammal (i.e. compared to horses we take years longer to gain independence),* the biological imperative is for there to be a strong bond between mother and offspring consummated in the act of breastfeeding.
Breast milk, therefore, contains actual morphine. This is to ensure that a very close bond forms and that the offspring will seek out and obtain nourishment by garnishing physical dependency.
The fact that our first food -- breast milk -- contains opiates and that the biosynthetic pathway for morphine exist in tissues such as the liver, blood and brain, indicate that our species was destined to be drawn to substances that either mimic the action of opiates, or modulate their secretion and/or activity within our bodies.