Digestion is a complex process that draws blood from the brain, muscles, and other systems. After heavy meals most of the blood from the brain and muscles (sympathetic nervous system) moves to the digestive tract (parasympathetic nervous system) and the brain is deprived of blood and hence oxygen. This explains why one falls asleep after a heavy meal and the old adage that one shouldn’t swim (or perform other exercise) for 2 hours after eating.  The system needs uninterrupted rest to perform digestion properly (‘rest and digest!’); otherwise a sudden demand for blood via the sympathetic system will override the digestive needs and shift to ‘fight or flight’ mode via adrenaline and other signals. Running away from a tiger is, after all, more important than digesting your meal.  While this override is a great immediate hack for survival of our species, in the long run it may cause problems. Improperly digested food will sit in our systems as a growth ground for unwanted organisms and toxins.

Fruits and vegetables take a short time in the digestive tract. Proteins and carbohydrates take relatively longer. If retained in the digestive system for too long, proteins putrefy, while sugars and carbohydrates ferment. This makes the mono-meal optimal (eating one food at a time). When combining foods, one should know the right foods to combine to ensure that all the blood is not channeled to digestion. This frees up blood for the brain and muscles. The right combinations ensure better digestion, absorption, assimilation, and elimination of food. Excellent nutrition and better health is guaranteed with proper food pairing.

Food Combining Rules

Proteins and Carbohydrates

Proteins and carbohydrates are digested differently and are also some of the most difficult foods to digest.  Digestion of carbohydrates starts in the mouth with the enzyme amylase in saliva following an alkaline process; while digestion of proteins commences in the stomach by pepsin and hydrochloric acid. When carbohydrates and proteins are mixed in the stomach, they obstruct the digestion of each other since an acidic and alkaline process cannot take place concurrently. The primary explanation is: if a concentrated protein and a concentrated starch (meat and potatoes, or your favorite burger) are consumed together the enzymes neutralize each other, and no digestion takes place. According to another school of thought, Dr. John Marshall argues that the rising acidity in the stomach halts the carbohydrate digestion since the undigested starch absorbs pepsin, therefore increasing hydrochloric acid which renders the proteins indigestible. This explains why beans are hard to digest; they contain approximately 25% protein and 50% carbohydrates. According to Prof Mc Collum as the protein is being digested the carbohydrates are not digested and therefore ferment producing gas and toxins. Proteins and carbohydrates should therefore be eaten separately, and are better combined with vegetables.

Proteins and Proteins

One protein at a meal should be adequate. This is because proteins are different and have different compositions, therefore requiring different digestive processes. This means that foods like meat, nuts, eggs and milk should never be combined in one meal. According to Daniel Reid, the strongest enzymatic action on milk occurs during the last hour of digestion, meat in the first hour and eggs in between. Milk should always be consumed alone because it is a complete food. Proteins are hard to digest and combining them makes digestion more difficult, and it actually takes longer, and an overload of amino acids overloads the liver. They are best combined with non-starchy vegetables, mildly starchy vegetables, and ocean vegetables.

Proteins and Fats

These food groups should never be combined. Fat inhibits the production of gastric acids by depressing gastric glands. This means that butter, cream, and oil should never be consumed with meat, eggs, and nuts. Fats are also broken down by bile from the liver and gall bladder and mixing them with gastric acids complicates digestion. Donna Gates author of The Body Ecology Diet argues that a combination of proteins and fats only slows digestion. Proteins and fats should only be combined with vegetables, and they should only be combined with pure unrefined oils like olive and coconut.

Carbohydrates and Acid Foods

Potatoes, bananas, and bread should not be accompanied by limes, oranges, and pineapples. Amylase that starts the digestion of carbohydrates in the mouth only acts in an alkaline environment. When eaten together ptyalin is destroyed by the acid preventing the digestion of carbohydrates and facilitating their fermentation. Tomatoes contain citric, oxalic and malic acids and should never be paired with carbohydrates because they completely inhibit alkaline digestion. This explains why pizza and pasta are considered ‘unhealthy.’

Proteins and acid foods

Proteins require an acid medium for digestion, but ironically pairing them with acidic fruits like oranges and pineapples does not facilitate digestion. According to Daniel Reid acid foods inhibit the secretion of hydrochloric acid and pepsin, rendering the proteins indigestible, and resulting in putrefaction.

Starch and Sugar

Cereal with sugar jams and jellies with cake and bread are a perfect recipe for fermentation.  It has been observed that when sugar is ingested the mouth quickly fills with saliva that lacks amylase which is essential for starch digestion. This combination inhibits the digestion of starch resulting to fermentation and generally indigestion.

The following is an excerpt of “Men’s Health Magazine,” see works cited.

According to Men’s Health Magazine, the following are awesome synergistic combinations;

Tomatoes & Avocados

Tomatoes are rich in lycopene, a pigment-rich antioxidant known as a carotenoid, which reduces cancer risk and cardiovascular disease. Fats make carotenoids more bioavailable, a fact that makes a strong case for adding tomatoes to your guacamole.

“This also has a Mediterranean cultural tie-in,” says registered dietitian Susan Bowerman of California Polytechnic State University. “The lycopene in tomato products such as pasta sauce is better absorbed when some fat (e.g., olive oil) is present than if the sauce were made fat free.” This may also explain why we love olive oil drizzled over fresh tomatoes.

And when it comes to salads, don’t choose low-fat dressings. A recentOhio State University study showed that salads eaten with full-fat dressings help with the absorption of another carotenoid called lutein, which is found in green leafy vegetables and has been shown to benefit vision. If you don’t like heavy salad dressing, sprinkle walnuts, pistachios, or grated cheese over your greens.

Oatmeal & Orange Juice

A study from the Antioxidants Research Lab at the U.S. Department of Agriculture shows that drinking vitamin C-rich orange juice while eating a bowl of real oatmeal (read: not processed) cleans your arteries and prevents heart attacks with two times as much efficacy than if you were to ingest either breakfast staple alone. The reason? The organic compounds in both foods, called phenols, stabilize your LDL cholesterol (low-density lipoprotein, or so-called “bad” cholesterol) when consumed together.

Broccoli & Tomatoes

New research shows that this combo prevents prostate cancer, but no one is sure why.

In a recent Cancer Research study, John W. Erdman Jr., Ph.D., of the University of Illinois, proved that the combination shrunk prostate-cancer tumors in rats and that nothing but the extreme measure of castration could actually be a more effective alternative treatment. (What more motivation do you need to embrace this one-two punch?)

“We know that tomato powder lowers the growth of tumors,” says Erdman. “We know that broccoli does too. And we know they’re better together. But it’s going to take years to find out why.”

Blueberries & Grapes

“Eating a variety of fruit together provides more health benefits than eating one fruit alone,” says Bowerman. “Studies have shown that the antioxidant effects of consuming a combination of fruits are more than additive but synergistic.”

In fact, a study published in the Journal of Nutrition by Rui Hai Liu, Ph.D., from Cornell University’s department of food science, looked at the antioxidant capacity of various fruits individually (apples, oranges, blueberries, grapes) versus the same amount of a mixture of fruits, and found that the mix had a greater antioxidant response. According to the study, this effect explains why “no single antioxidant can replace the combination of natural phytochemicals in fruits and vegetables.”

The author also recommends eating five to 10 servings of a variety of fruits and vegetables daily to reduce disease risks, as opposed to relying on expensive dietary supplements for these compounds. “There are a huge number of compounds yet to be identified,” adds Jacobs.

Apples & Chocolate

Apples, particularly Red Delicious, are known to be high in an anti-inflammatory flavonoid called quercetin, especially in their skins. (Note: It’s important to buy organic because pesticides concentrate in the skins of conventionally grown apples.) By itself, quercetin has been shown to reduce the risk of allergies, heart attack, Alzheimer’s, Parkinson’s, and prostate and lung cancers.

Chocolate, grapes, red wine, and tea, on the other hand, contain the flavonoid catechin, an antioxidant that reduces the risks for atherosclerosis and cancer. Together, according to a study done by Barry Halliwell, Ph.D., a leading food science professor at the National University of Singapore, catechins and quercetin loosen clumpy blood platelets, improving cardiovascular health and providing anticoagulant activity. Quercetin is also found in buckwheat, onions, and raspberries.

Susan Kraus, a clinical dietitian at Hackensack University Medical Center in New Jersey, recommends the following combinations: sangria with cut-up apples; green tea with buckwheat pancakes and raspberries; and kasha (roasted buckwheat, made in a pilaf) cooked with onions.

Lemon & Kale

“Vitamin C helps make plant-based iron more absorbable,” says nutritionist Stacy Kennedy of the Dana Farber Cancer Institute. It actually converts much of the plant-based iron into a form that’s similar to what’s found in fish and red meats. (Iron carries oxygen to red blood cells, staving off muscle fatigue.)

Kennedy suggests getting your vitamin C from citrus fruits, leafy green vegetables, strawberries, tomatoes, bell peppers, and broccoli, and getting plant-based iron from leeks, beet greens, kale, spinach, mustard greens, Swiss chard, and fortified cereals.

So whether you’re sautéing dark greens or making a salad, be sure to include a squeeze of citrus. You’ll increase your immunity and muscle strength with more punch than by eating these foods separately.

Soy & Salmon

it’s true that soy has been shown in studies to lower sperm counts, but that’s mainly in processed forms such as soy cheese, soy milk, and the unpronounceable forms listed on the labels of your favorite artery-clogging processed foods. This means that eating unprocessed forms of soy, such as edamame and tofu, is perfectly fine in moderation.

That’s good news because, according to Mark Messina, Ph.D., former director of the diet and cancer branch of the National Cancer Institute at the National Institutes of Health and now an adjunct associate professor at Loma Linda University, an isoflavone in soy called genistein inhibits enzymes in the colon and prostate, raising the amount of vitamin Bioavailability in those tissues. “The higher vitamin D levels may offer protection against cancer,” says Messina. “There is emerging research suggesting that vitamin D reduces cancer risk, and many people don’t get enough of the vitamin. You do make it in your skin, but most people don’t make enough.”

Fish such as salmon and tuna are high in vitamin D, so take a cue from the Asian diet and eat fish with a side of edamame.

Peanuts & Whole Wheat

According to Diane Birt, P.D., a professor at Iowa State University and a food synergy expert, the specific amino acids absent in wheat are actually present in peanuts. You need, and very rarely receive in one meal, the complete chain of amino acids (the best form of protein) to build and maintain muscle, especially as you get older. In short, while this combo exhibits only what Birt calls a “loose definition” of food synergy, it gives good evidence that a peanut-butter sandwich isn’t junk food if it’s prepared with whole-wheat bread (not white) and eaten in moderation (once a day).

So enjoy a peanut-butter sandwich right after a workout instead of drinking a terrible gym-rat shake. Just make sure the peanut butter doesn’t have added sugar, chemical ingredients you can’t pronounce, or cartoon characters on the label.

Red Meat & Rosemary

Grilling over an open flame produces nasty carcinogens, but if you get a little more experimental with your spices, you can temper the cancer-causing effects of the charred flesh.

The herb rosemary, which mixes well with all kinds of grilled foods and contains the antioxidants rosmarinic acid and carnosic acid, was recently shown in a Kansas State University study to lower the amount of the cancer-causing heterocyclic amines (or HCAs) that appear in the charred meat when you grill at temperatures of 375°F to 400°F. Why? It’s thought that the herb’s antioxidants literally soak up the meat’s dangerous free radicals.

Turmeric & Black Pepper

A tangy yellow South Asian spice used in curry dishes, turmeric has long been studied for its anticancer properties, anti-inflammatory effects, and tumor-fighting activities known in nutrition-speak as anti-angiogenesis. The active agent in the spice is a plant chemical, or polyphenol, called curcumin.

One of the problems with using turmeric to improve your health, according to Kennedy, is its low bioavailability when eaten on its own. But there’s a solution, and it’s probably in your pantry.

“Adding black pepper to turmeric or turmeric-spiced food enhances curcumin’s bioavailability by 1,000 times, due to black pepper’s hot property called piperine,” says Kennedy. “This is one reason it’s thought that curry has both turmeric (curcumin) and black pepper combined.” Translation: You’ll get the benefits of turmeric if you pepper up your curries.

Garlic & Fish

Most seafood lovers don’t realize there’s a synergy of nutrients inside a piece of fish: Minerals such as zinc, iron, copper, iodine, and selenium work as cofactors to make the best use of the natural anti-inflammatory and cholesterol-reducing fish oils EPA and DHA.

What’s more, cooking your fish with garlic lowers your total cholesterol better than eating those fillets or cloves alone. A study at University of Guelph, in Ontario, found that garlic keeps down the small increase in LDL cholesterol that might result from fish-oil supplements.

Eggs & Cantaloupe

The most popular (and an awfully complete form of) breakfast protein works even better for you when you eat it with the good carbohydrates in your morning cantaloupe.

According to Kennedy, a very basic food synergy is the concept of eating protein with foods that contain beneficial carbohydrates, which we need for energy. Protein, Kennedy reminds us, slows the absorption of glucose, or sugar, from carbohydrates.

“This synergy helps by minimizing insulin and blood-sugar spikes, which are followed by a crash, zapping energy. High insulin levels are connected with inflammation, diabetes, cancer, and other diseases. By slowing the absorption of glucose, your body can better read the cues that you are full. This helps prevent everything from overeating to indigestion.”

So cut as many bad carbs (i.e., anything white, starchy, and sugary) as you want. But when you eat healthful carbs (whole grains, fruit, vegetables), don’t eat them on their own.

Almonds & Yogurt

We already know that good fats help increase lycopene absorption. But did you know that many essential vitamins are activated and absorbed best when eaten with fat?

Vitamins that are considered fat-soluble include A, D, and E. Carrots, broccoli, and peas are all loaded with vitamin A and should be paired with a healthy fat such as the kind found in olive oil. Vitamin D—rich products include fish, milk, yogurt, and orange juice.

So toss some almonds into your yogurt, eat full-fat dairy foods, and pair your morning OJ with a slice of bacon. To get the most vitamin E with fat-soluble foods, try baked sweet-potato slices or spinach salad topped with olive oil. ( Extracted from Men’s Health Magazine)

Sources

1. Baer, Adam. “The Most Powerful Food Combinations.” Men’s Health. 2015 April 7.  <http://www.menshealth.com/nutrition/powerful-food-combinations>
2. David Klein, Ph.D., H.D. “Is Your Food Digesting or Rotting in Your Gut?” Colitis & Crohn’s Health Recovery Center. <https://davidkleinphd.wordpress.com/2010/01/25/is-your-food-digesting-or-rotting-in-your-gut/>
3. Francis, Raymond, Kester Cotton, and Harvey Diamond. Never Be Sick Again: Health Is a Choice, Learn How to Choose It: One Disease, Two Causes, Six Pathways. Deerfield Beach, FL: Health Communications, 2002. Print
4. Gates, Donna, and Linda Schatz. The Body Ecology Diet: Recovering Your Health and Rebuilding Your Immunity. 10th ed. Decatur, GA: Body Ecology, Bogart, Georgia, U.S.A., 2006. Print
5. Marshall, J. J. (1975) Am. Chem. Sot. Symposium Series 15, 244- 266
6. Reid, Daniel P. (1989). The Tao of Health, Sex and Longevity. New York: Simon & Schuster Ltd.