What foods are good and bad for you?

In developed countries where many people have an abundance of food and the luxury of choice, there also tends to be some level of anxiety about eating ‘correctly’, with people being bombarded with conflicting advice about what is good and what is bad for you. For those who do like to be better informed about this, this article explores some of the myths and summarizes the research on various foods that have been either praised or demonized: coffee, alternative milks, red wine, red meat, and carbohydrates. The article goes into some detail on the research on each but I will excerpt just some of the stuff on coffee, one of the demonized items.

“I’m surprised that people still think coffee is bad for them,” says Dr Astrid Nehlig, research director of the French medical research institute, Inserm, and one of the world’s leading researchers into coffee, health and brain function.

So what do we know, now? “Coffee contains more than 1,000 compounds, so what we are looking at is not just about caffeine,” says Nehlig. “It increases alertness but at the same time relaxes us. It focuses and increases attention, but prevents sleep, especially if you drink too much, or too late.” We are not all equal on this front: caffeine targets our brain’s adenosine receptors but half of us are immune to this effect – which explains all those people who drink espresso after dinner and conk out at 11pm. “It’s also about the accumulation of caffeine during the day, which is related to how we metabolise caffeine – in one group of the population, caffeine builds up in the body, but the other group eliminates it very quickly.”

Nehlig adds: “Coffee has often been accused of being bad for heart health. But we now have global research showing that coffeeit is protective against cardiovascular disease, stroke and coronary heart disease, and decreases mortality linked to cardiovascular issues.” Nehlig says there is also clear evidence that coffee protects against type 2 diabetes, regardless of body fat; it’s definitely protective against Parkinson’s disease and almost certainly against cognitive decline in general. Coffee does not increase our risk of cancer. “It’s neutral, or even protective in some cancers, like the liver, colon, endometrium and some non-hormonally dependent breast cancers.” Quite why this is, isn’t yet known; Nehlig’s hunch is that it’s to do with coffee’s range of antioxidants.

This isn’t a licence to knock back as many flat whitesas possible, though. “Research shows adults shouldn’t go over 400mg a day, which is 4-5 small cups, and no more than 200mg in one sitting.” (Coffees from high-street chains can contain as much as 300mg in a large serving.)

“For some people caffeine will either trigger anxiety or worsen symptoms of anxiety,” says Murray Carpenter, author of Caffeinated: How Our Daily Habit Hooks, Helps and Hurts Us. “Some who really suffer from anxiety have never experimented with eliminating or minimising caffeine.” (My own anxiety got so bad that I had to give up caffeine during the worst of the pandemic in 2020. I still miss it.) Caffeine also worsens insomnia. “In both scenarios, I think it’s important that people experiment with changing their caffeine habits and see what improves,” says Carpenter. It won’t be a silver bullet for everyone. “But if you don’t experiment, you won’t know.”

Especially as one gets older, statistical analyses about marginal effects on longevity tend to be less salient since one’s life expectancy is not that great. I myself tend to not worry about what I eat as long as I practice moderation and follow food writer Michael Pollan’s general advice to “Eat food. Not too much. Mostly plants.” Within that general framework, I eat food that I enjoy eating and not worry about the health effects.


  1. Katydid says

    Beyond broad statements about nutrition, it all depends on the person as to which foods are better for them and which are worse. For someone with celiac disease, bread and baked goods are not good for them. Whole grain is not good for them. But they may be very good for other people to eat.

    For someone who is lactose intolerant, dairy products are not good for them. For others, dairy products are a staple.

    To use your example of coffee; if someone cannot tolerate caffeine, coffee is not good for them. For others, it is a very good choice.

    We are not all the same in our nutritional needs and abilities.

  2. anat says

    There are a few generalizations: Ultra-processed foods are not great for anyone, though a small amount can be tolerated with little harm. How small depends on the person.

    The biggest problem with ‘everything in moderation’ is that our concept of moderation depends on what we consider normal. For instance currently Americans eat way more sugar than Americans did in the 19th century, so what we would consider moderate sugar consumption would have been extremely high consumption back then.

    Similarly the idea of eating from all ‘food groups’ is meaningless, as the concept of ‘food groups’ is cultural and depends on what foods are commonly consumed in a specific culture, what foods are valued, considered important etc.

    Regarding coffee: From my reading, the benefits seem to kick in at 3-4 cups a day. I have never been able to drink more than 2 cups a day routinely, usually less. And my sleep is terrible -- I went through times when I would wake up a lot and lie awake for extended periods many nights. So I quit coffee completely. It helped. I still can’t make myself sleep more than 6 hours a night, but at least I don’t lie awake so much time.

  3. moarscienceplz says

    I like Michael Pollan’s epigram, but I would add, “Try to eat as many different foods as possible.”
    Also, I think each person has to pay attention to their own body. I can drink a cup of black tea at 10 PM and it acts as a soporific for me. OTOH, I am experimenting with intermittent fasting, where I try to eat no calories after dinner for 12 to 14 hours. ( I don’t do this every day). I have lost a good amount of excess pounds, but I find that my morning tea can cause diarrhea when I am fasting.

  4. says

    Ultra-processed foods

    What’s that?
    A lot of the stuff like, say, partially hydrogenated palm oil is easier to make (less processing) than, say, bacon. Is something salted and smoked “ultra processed”? Or does a nuclear reactor have to be involved? Are my mashed potatoes ultra processed? Sauce demi-glâce is probably the most processed food around. I’m not sure the term has any meaning.

  5. Katydid says

    Also, food prohibitions are not only a product of upper-class Americans. Orthodox Jews and Muslims don’t eat pork, for example. The Old Testament--the oldest parts are thought to be 1200 years old--prohibits shellfish and some other things. In medieval Europe and parts of Scandinavia, they thought tomatoes and cucumbers were poison.


    What’s not good for you may not become apparent for years. As a retired person, I look from the other end of the magnifier. The dominant cause of death in the US is heart and circulatory issues. We clog ourselves up with sugar and refined carbs. Start there rather than with isolated food studies. So after a heart attack five years ago I researched, decided one and a half tablespoons a day was an input the body could handle, and changed my diet accordingly. Mostly the sugar/carb rations are saved for things like birthday cakes and holiday desserts. The results are all good. There’s a lot more out there on how people got smaller with smaller brains as a result of agricultural grains, but their children lived and populations grew.

  7. xohjoh2n says


    I’m not sure the term has any meaning.

    Of course it does, it means “my eating preferences make me morally superior to you”.

  8. anat says

    Regarding the definition of ultra-processed foods (which have been discussed on this blog recently) see https://world.openfoodfacts.org/nova There are issues with the definition, so better not take it too literally, but get the general idea. (According to Michael Pollan they simply aren’t included in what he means by ‘food’).

    Yes, partially hydrogenated oils are ultra-processed Oils that are not partially hydrogenated are in category 2: ‘processed culinary ingredients’. One of the big problems with ultra-processed foods is that they are under-satiating per caloric content consumed compared to equivalent minimally-processed foods. See Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake You can also

  9. John Morales says

    Big difference between drinking a glass of unsweetened orange juice and eating 4-5 oranges.

    (Who the hell eats that many oranges at one sitting?)

    Big difference between 100g of strawberries and 100g of strawberry jam.

    That sort of thing.

    (I know which one is preferred by a typical alimentary tract)

  10. chigau (違う) says

    I don’t drink coffee because it tastes very much like shit.
    Not for any moral reasons, it is just foul.

  11. says

    The downside of a lot of coffee is the caffeine addiction. Not the need to drink, but the headaches from the withdrawal. If I don’t have one withing 12-14 hours of waking up, I feel it.

    The odd thing about getting older is no longer getting a blood pressure spike after drinking it. In my forties, I would see a jump of 30 on the systolic (first number) and 20 on the diastolic. In the last few years as I hit mid-50s, nothing.

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