Sometimes you can be really picky and only eat certain foods that exactly meet your needs. Other times you might be willing to be less stringent in order to avoid going hungry, or to avoid spending an excessive amount of time checking every single detail about your food source.

There are people who will follow food recommendations very strictly at home, where they have full control over all the ingredients; but when they go out they follow “label” diets — for example, a vegetarian in a restaurant might not be so strict about whether the cheese in the dish they are eating contains rennet, which is an animal by-product. The people in the restaurant are unlikely to realize that this is important to some people, and the diner may not get a clear answer even if they asked about it.

Some other people might buy certain manufactured food or food from restaurants that follows their diet strictly, because someone else has gone to all the trouble needed to meet their requirements; but when getting foods on the fly they might not want to follow all those complex rules.

People may follow a diet or food recommendation socially — when they’re eating with other people, they’ll eat low fat or macrobiotic or whatever everyone else is eating, so they fit in. Even if they imply to everyone around them that they always do this, they might not be that strict if nobody from this group is watching. Overweight people are more likely to pick at their food or choose diet options in public because they are concerned that other people are judging them — even if they don’t overeat in private, they may still feel a stigma and be very careful about how they present their eating habits.

Do you have any food habits that are different depending on where you’re eating or who you’re eating with?

For someone with an allergy, avoiding a tiny piece of food may be a matter of life or death. If your cookie has a small piece of peanut in it from the previous batch, and you’re allergic to peanuts, it could cause anaphylactic shock and potentially death. It’s really obvious why some people should avoid foods “contaminated” with certain ingredients for health reasons. But there are also other reasons for avoiding food contaminants.

Would you mind eating just a little bit of human flesh in your food? You probably wouldn’t feel comfortable with that. How about food from a pan that had recently been used to cook human flesh, and not cleaned out afterwards? Probably a problem for you as well. Ethical vegetarians who don’t want to harm animals may have the same reaction to meat dishes. The same goes for people who have who follow non-violent religions such as Hinduism, Buddhism, or Jainism — they don’t want to be party to a process that harms any animals.

If you sneak some alcohol into the food of an observant Muslim following Halal laws, or put bacon into a dish for an observant Jew following the Kosher food laws, you’re contaminating their food. They don’t want to eat those foods, and even if they eat banned foods by mistake they may consider that they’re breaking an important law and would feel terrible about it.

Many foods have hidden or semi-hidden ingredients. Most Worcestershire sauce has a small amount of anchovies (fish) in it, so adding it to a vegetarian dish stops the dish from being truly vegetarian. Many noodles contain eggs, and so they aren’t suitable for lacto-vegetarians, who will eat milk products but not eggs.

Occasionally, manufactured foods don’t contain exactly what they say on the ingredients list or nutrition panel. This may happen with small, local companies without the resources to properly track this, or who may be willing to bend the rules to get sales because they’re too small to get found out. For example, there may be some fat in fat-free products. This is pretty rare, but it can happen.

Are there any ingredients that you have to look out for, that sometimes get sneaked into foods you want to eat?

Some people will only eat certain types of food at certain times of the day; others will wait a prescribed amount of time between eating one type of food and another; and some people will eat or avoid foods on particular days of the week, times of the year, or holidays, or their eating habits might depend on health conditions.

There are social expectations for the timing of eating foods. Most Westerners won’t eat spicy foods for breakfast, although that’s normal in India and some other countries. People are expected to eat dessert at the end of a meal, not at the beginning.

Combining diets, based on the Hay Diet from the 1920s, suggest that you should eat fruits in the morning and nothing else for 1/2 hour so the fruit can work its way through the digestive system without getting clogged up by other types of food and then fermenting. They also suggest having proteins and carbohydrates in separate meals, with a space in between. Other diets suggest eating carbohydrates in the morning, or proteins in the morning, having a large meal only in the middle of the day, having a large meal late at night, eating carbohydrates at night… there are lots of different recommendations from different authorities that can’t all be followed at the same time.

A number of religions have fasts, often in the spring when winter supplies are running out and leafy green vegetables are first available again after winter. For Eastern Orthodox Christians, the period of Lent may be a time when they have to avoid many foods — their diet becomes almost vegan. They also have numerous other fast days and periods throughout the year. Western Christians also restrict food during Lent, but the restictions are less comprehensive.

Ramadan, the major religious holiday for Muslims, is at a different time each year. Nothing may pass the lips during daylight hours, and there is feasting at night. Some Hindu festivals involve fasting as well as feasting. Jewish fasts and food-related holidays include Sabbath, every Saturday, during which you are supposed to eat three meals, and the bread called challah is usually eaten. During Pesach (passover) in the springtime, no leavened (risen) bread may be eaten. Yom Kippur is a fast day, people eat fried foods on Chanukah, and dairy is eaten on Shavuot. This is an extremely brief description for a very complex set of food-related holidays!

According to the Jewish laws of Kosher, you shouldn’t combine meat and milk. Eastern European Jews may wait 6 hours after eating meat before having milk, Germans 3 hours, and some Dutch Jews may wait 1 hour. Between eating dairy and meat, they rinse their mouths and eat a solid food like bread — there may be more rinsing and chewing involved if the milk food tends to stick in your mouth.

People who want to eat seasonally might only eat fruits and vegetables at the time of the year when they could be harvested in their local area — no tomatoes or peaches in the middle of winter, unless they’ve been preserved.

Sometimes people have to time eating for health reasons. They might not eat anything for a certain number of hours before an operation. They may have to eat when taking a medication that has to be eaten at the same time every day. Diabetics taking insulin have to control what they eat and when, so their blood sugar can stay level. Pregnant women may avoid certain foods during pregnancy when they are immunocompromised, and then start eating them again after they give birth.

Are there any foods you eat or avoid at certain times?

We might make food combination choices for reasons of health, or beliefs, or taste.

In the Middle Ages in Western Europe, it was normal to put fruits and sweet spices into meat dishes. This is still true in some North African and Chinese cuisines, but doesn’t happen so often any more in Western cuisines. We may think that certain foods “belong” with each other, and that sweet and savory tastes shouldn’t be combined of they just taste wrong.

Some diets advise against combining certain foods. The Hays diet in the 1920s set the precedent for many of these, and it’s a set of recommendations that comes in and out of fashion. The scientific name sometimes used for food combining is trophology. The basic idea is that your body isn’t designed to digest all different types of food at the same time. Your stomach needs a lot of acid for several hours to digest meat and animal proteins, but carbohydrate digestion needs an alkaline environment. There are detailed rules about which types of food can be eaten together (eg. proteins may be eaten with salads), and which should be eaten separately (eg. melons should not be eaten with any other foods).

Ayurveda, the traditional medicine system in India, advises against combining acid foods such as fruits together with milk, because of the belief that they will curdle in the digestive system. It also advises against eating a lot of cooked food and raw food together, and eating fresh foods with leftovers.

Under the Jewish Kosher system, meat and milk should not be mixed together, and a certain amount of time should pass between eating one and the other.

Sometimes it’s advised to combine foods to potentiate them — eating them separately brings benefits, but when eating them together 2+2=5. For example, pulses or beans and grains eaten together are said to provide the full spectrum of essential amino acids, the protein components we can’t produce ourselves and need to get from foods. Separately, each of them does not provide the full spectrum. Some vitamins are fat soluble — A, D, E, and K — and a small amount of fat is needed for them to be absorbed into the digestive system.

When you have combining, you have issues of timing, which are discussed separately.

Which foods do and don’t you eat together?

There are recipe books for diabetics, and for people on low fat diets. Manufactured foods are produced for the gluten-intolerant and for people who want low-carb diets. Restaurants offer vegetarian options.

It’s easy to put labels on people and put them into baskets for food preferences. But reality isn’t that simple.

A person on a low fat diet may also be lactose intolerant and dislike leafy green vegetables. A diabetic may also try to avoid red meat and to separate carbohydrates from proteins. You might find someone who wants to minimize potassium and iron intake but increase vitamin C, while avoiding high fructose corn syrup. And the reality is usually a lot more complex than this — a person may have a list of food preferences as long as their arm.

Sometimes it seems as though young people can eat anything without being adversely affected by it. They may be able to booze all night without worrying too much about the resulting hangover, and follow this up iwth a huge high-carb, high-fat breakfast without putting on any weight or thinking they may have a heart attack.

As we get older, we’re less able to do these kinds of things without discomfort. We put on weight, get acid reflux, worry about heart disease and diabetes, maybe discover that the reason we’ve had a minor symptom all these years is because of some type of food intolerance. We go from having few conditions to multiple conditions, and a complicated array of food requirements to meet our personal cocktail of conditions and recommendations to follow.

So, even if someone only uses one label to describe their eating habits, they probably also have an increasing number of other food choices for other reasons.

Do you have a really complex set of food preferences? How about someone you know?

Some food choices may be made for multiple reasons, or reasons that don’t fit into simple categories. Most people in the West won’t eat dogs. Is this for philosophical or psychological reasons? Dogs are our friends, so we should not eat them — philosophical / beliefs. Yeuch, how could anyone eat a dog? — psychological / gut feelings.

People may be vegetarian for multiple reasons. Philosophical — you shouldn’t harm creatures, or the environment; or my religion tells me not to eat meat. Psychological — yeuch, that steak was a living animal not long ago. Physical/health — they might believe it’s healthier not to eat saturated fats / too much protein / some other aspect of meat; we’re not designed to eat meat; it’s healthier not to.

If you eat or avoid certain foods because you’re part of a group, you may be doing so partly for philosophical reasons (it’s my belief that I should / should not eat this). But it may also be for psychological reasons (I want to fit in to this group, so I need to do what they do)

Speaking of fitting in: Weight loss, or sometimes weight gain, can be desired both for physical / health and psychological reasons. It may be healthier to be a “normal ” weight, and some people will also try to get there to avoid feeling socially ostracized.

A person might minimize the amount of fish they eat for the philosophical reason that they are concerned about the overfishing of the world’s oceans, and also because they have the physical / health issue that they’ve had food poisoning from fish a few times.

Where do you think this one fits? Some people will not choose foods because they’re more expensive than they think they’re worth.

Are there any foods that you eat or avoid for multiple reasons?

Some people choose and avoid foods based on their belief system. Formal beliefs include religions; informal philosophies include vegetarianism and other moral reasons for choices.

Vegetarianism has been around for thousands of years; Buddha and Pythagoras were avoiding meat 2 1/2 thousands years ago. It’s a philosophy that comes in and out of popularity. Nowadays around 18 million Americans, 6% of the population, describe themselves as vegetarian, although quite a few of them eat meats occasionally, only less often than other people. Under a stricter definition of vegetarianism, avoiding meat, poultry, and fish, the number is more like 5 million, under 2%.

Many, but not all, vegetarians make this choice for ethical reasons. Some may be vegetarian because of their religion, and others for health. Ethical vegetarians might be horrified at the idea of eating animals, or disgusted at the living conditions they’re raised in.

A number of religions have food restrictions. Some examples: Kosher laws are probably the most complicated of these. Muslim Halal laws are a lot simpler. Buddhism and Hinduism both avoid unnecessary violence and advise against eating meat. Many observant Christians give up certain desired foods for Lent; some go on a semi-fast. Seventh Day Adventism also calls for vegetarianism. Strict Mormons aren’t supposed to consume caffeine or alcohol. Millions of Americans follow some type of religious food restriction.

Another reason for choosing foods based on philosophy is environmental. Some examples: If you believe that foods should be grown in their natural environment and not in greenhouses at unusual times of the year, you may want to eat seasonally. If you think that excessive use of man-made fertilizers, pesticides, hormones, and antibiotics are unnatural and should be avoided, you may want to eat organic food. If you’re concerned about the overfishing of the world’s oceans and dying species of fish and shellfish, you may want to minimize your seafood intake.

Sometimes people take a moral stance about a country or company or group of individuals, and one way they “punish” them is to avoid their foods, which may be an important part of their economy. In the 1980s some people avoided fruits from South Africa to punish the apartheid regime. There are people who will avoid certain food manufacturers because of their policy of selling powdered milk to poor nursing mothers in the third world.

Do you have any philosophical food decisions? What do you believe you should or shouldn’t eat?

Cupcake or okra?

We’re designed to prefer certain foods, and dislike others — this helps keep the species alive. However, we’re designed with a certain amount of flexibility. Throughout our lives, we can learn to change our likes and dislikes.

Bitter foods may be poisonous, slimy ones may contain bacteria, moldy foods may contain poisonous fungi. Not all of them do, but we’re designed to avoid them just in case. Underripe fruits are sour and grainy/mealy — we’re designed to avoid these sensations because ripe fruit provides more energy and underripe fruit can cause digestive problems. When we’re young, our initial reaction to these tastes and mouthfeels is dislike. But if a parent who loves you keeps feeding you foods with one of these properties, with a smile on their face and maybe alongside a food you enjoy, and they enjoy it themselves, you’ll end up liking that food as well. Blue cheese may appear horrible to the uninitiated, but to some people it’s delicious. There’s a cultural element in this — for example, many Asian cultures love bitter foods, the more bitter the better, but give them a smelly cheese and they’re probably going to dislike it.

On the other hand, we’re naturally attracted to sweet and fatty foods. They provide a lot of energy, which is essential in survival situations. Luckily most of us are unlikely to starve — unluckily we still enjoy these foods and mouthfeels, and this makes it harder for use to balance energy consumed and energy expended. So we put on weight.

Sometimes an external factor affects these natural, unconscious thoughts. If you eat a certain food and get sick afterwards, you might unconsciously (or even consciously) think that the food made you sick. It might be totally illogical — something else completely may have made you sick — but you won’t feel able to eat that food ever again.

Many of us grew up with a few familiar foods that we ate time and again. For some people, a dish cooked even slightly differently from how their mom cooked it is just “wrong.” There are endless discussions about what is the “right” chili or barbeque style.

Comfort from familiarity also happens on a national level. Until the 1950s, in most of the West yogurt was a strange food that people wouldn’t even try because it sounded foreign. It took decades to come into general acceptance. We tend to like cuisines we’re familiar with, and it’s not unusual to dislike a food or cuisine because you weren’t exposed to it at an early age.

Most people try to fit into society, and accept the social norms of eating. You’re more likely to like a food if your friends like it. In the West, insects aren’t considered a food at all, and most people think that organ meats are horrible. In some other cultures, these are perfectly normal to eat, and even savored. There are fashions in food — foods in aspic were all the rage in the 1970s, but nowadays many people would turn up their noses at them.

Alternatively, some people may eat or avoid different foods, in order to stand out from a group they want to be different from.

What foods do you just love, or just hate, without any logical reason, apart from “yum” or “yeuch”?

Imagine there’s a food that most people can eat, such as peanuts, but it might potentially kill you. You’re going to keep a close eye out for it, and check everything you eat to make sure it’s not included.

Most people don’t have such extreme reactions to food. However, if you believe that a food might affect your health, and you’re motivated to protect yourself, you’re probably going to avoid the food if you think it’s bad for you or try to have more of it if you think it’s good for you.

Then there are a few well-known physical and health conditions that are tied to food recommendations:

Heart disease — According to the CDC, 25.1 million people in the USA, 11% of adults over age 18, have heart disease and it is the number one cause of death. Hypertension affects 52.9 million people, 24% of adults over 18. The American Heart Association recommends keeping track of calories, eating a variety of nutritious foods from all the food groups, and minimizing intake of fat, cholesterol, and salt.

Diabetes — The American Diabetes Assocation reports that 23.6 million people in the USA have diabetes, 7.8% of the population. 17.9 million are diagnosed, but 5.7 million don’t know they have it. It’s the 6th biggest cause of death. There are also 57 million people in the USA with pre-diabetes — blood glucose levels that are higher than normal but not yet high enough to be diagnosed with diabetes. The American Diabetes Association has similar healthy-food recommendations to the AHA. Diabetics using insulin have to plan the timing and size of their meals, and many have to control the amount of sugar and simple carbs they eat.

Food allergies — According to the American Academy of Allergy Asthma and Immunology, 6 1/2 million Americans, or 2.3% of the population, are allergic to seafood, more than 3 million are allergic to peanuts or tree nuts or both, and food allergies affect about 6% of children under the age of three.

And those are just a few of the big ones. Other conditions that may be affected by food include: acid reflux/GERD; headaches/migraines; cancer; arthritis; lactose intolerance; and celiac disease. People who are immunocompromised, including the very young, the very old, and pregnant women, have to avoid foods that most of us can eat because their defenses against food poisoning are minimal. Millions of people have trouble chewing and swallowing. Some conditions affect millions of people, others hundreds of thousands of people, and some affect very few people. To each of those people, their requirements are important. There’s a very long list of conditions potentially affected to food, and the number of solutions is even longer.

Many people want to lose weight for health reasons. 35% of USA adults are overweight but not obese, and 27% are obese, according to the National Health Interview Survey in 2008. The CDC survey behavioral risk each year in the BRFSS, and reported in 2005 that 46% of women and 33% of men were dieting. Other reports have suggested that 54 million, or 45 million, or 90 million Americans are dieting at any time. There are hundreds of weight loss diets, and it seems like another one is at the top of the bestseller lists every week. Some people will find a diet they like and stick with it or keep going back to it, while others will keep looking for the latest trends, believing that the new diet must be an improvement over the old ones.

In many cases, there are official recommendations and alternative health recommendations. People who are desperate to be healthy may look outside the regular medical community for possible cures. Also, official recommendations also change over time — we don’t yet know everything.

What foods do you choose for physical and health reasons? Is there anything you’d like to learn more about?

CDC — www.cdc.gov/nchs/fastats/default.htm
CDC National Health Interview Survey www.cdc.gov/nchs/nhis.htm
CDC Behavioral Risk Factor Surveillance System BRFSS www.cdc.gov/BRFSS
American Heart Association AHA www.americanheart.org
American Diabetes Association www.diabetes.org
American Academy of Allergy Asthma and Immunology www.aaaai.org

Everybody eats, but most people don’t eat everything. Even if someone says they eat everything, you’ll often find they avoid something — spinach, or organ meats, or insects, or smelly cheese.

We’re going to take a look at what types of food preferences people have — what people eat, and don’t eat, and why.

There are three main types of reason why people select foods: Physical, psychological, and philosophical.

Physical and medical reasons for choosing foods
People make food selections based on what they believe to be good for their health. People with health issues might follow eating recommendations from specialists, and someone allergic to peanuts will be very cautious to make sure they don’t eat something that will bring out an allergic reaction that might kill them.

Psychological reasons for food choices
Sometimes you just don’t like something. Maybe a food is slimy, or bitter, or at some point in your past you got sick after eating it. People who choose and avoid foods for psychological reasons don’t have a logical, or even conscious, reason for these choices, but they make them anyway.

Philosophical food choices
Many religions prescribe foods that people may and may not eat. Also, some people make food choices based on morals, such as not wanting to harm living creatures or the environment.

Multiple reasons
There are also many situations when a food choice doesn’t neatly fit into any of these categories. A person might be vegetarian partly because they don’t want to harm animals, and partly because they think it’s a more healthy diet. Someone on a weight loss diet may be doing it partly for health reasons but also partly because they don’t want to be seen as overweight, which is more of a psychological reason.

Next we’ll look at each of these in more detail.