Ask HN: What do we know about nutrition?
Are there some serious facts we know about nutrition or is it all marketing?
1. Everyone's "ideal" diet is different. Everyone's body, nutritional needs are surprisingly different. What works for one person won't work for another.
2. Most people seem to benefit from: eat whole (minimally processed, https://www.verywellfit.com/what-is-a-whole-foods-diet-22419...) foods, 2-4 times a day, eat to satiety but don't binge, exercise for at least 60min/day moderate intensity, treat yourself but only occasionally, visit your doctor and get lab work done regularly. General, boring advice you will hear from almost everyone, but it works. At least for most people, see 1)
1. Is red meat (e.g. beef steak) actually meaningfully unhealthy?
2. Is eating fat (e.g. what is on a steak) bad for you?
3. Is drinking a gallon of whole milk a day on top of your normal meals likely to lead to problems (i.e. blocked blood vessels, heart attack, stroke)?
4. Is fast food, e.g. a quarter pounder from mcdonalds, unhealthy?
It seems like what is conventionally known to be 'healthy' food also happens to be low-calorie food. I wonder if that is mostly because a lot of people are overweight, and so for them whatever makes them consume fewer calories is healthy?
To answer your questions:
- Red meat - we don't know (see https://www.reddit.com/r/nutrition/comments/ldaitn/is_red_me...)
- Fat is good for you, and saturated fat / cholesterol is fine unless you have certain genes that make you susceptible to heart attacks. Regular checkups / lab work should reveal this
- A gallon of milk a day isn't good, try to find more balanced ways to get your calories in
- Fast food is fine occasionally (e.g. once a week) but again, try to eat less processed high-calorie foods instead
Some examples of high-calorie whole foods: nut butters, fatty fish, cheese, yogurt, whole grains, potatoes, foods with with olive oil / butter
> It seems like what is conventionally known to be 'healthy' food also happens to be low-calorie food. I wonder if that is mostly because a lot of people are overweight, and so for them whatever makes them consume fewer calories is healthy?
Yes. What's healthy for a skinny person vs. an obese person vs. a sedentary person vs. a marathon runner is all different. For a starving person, even fast food and donuts are better than nothing. But, high-calorie whole foods are even better, because they have micro-nutrients as well as calories.
Lots of conventional diet advice (e.g. low-calorie = healthy) is geared towards the average American, and sadly lots of conventional diet advice sucks.
Many people have religious views with a nutrition component, and some will try latch onto any study that supports their view and push it while ignoring others that don't support it. Some will even go so far as to design a study to provide the results they want. Vegetarians are the most obvious example of this, but there are others.
Nutrition is hard to study even when you want to do the right thing. Most effects are small and so it takes a long time for anything to be measurable. People tend to be unable to stick to their assigned diet long enough for a controlled study to get real data. (the exceptions are confined to a hospital bed or prison cell - both of which add confounding factors that mean the study won't apply to normal people)
Attempts are made to work around the above with surveys. However people are bad at remembering what they ate yesterday, and tend to lie to make themselves seem "healthier" than they really are. As always when doing a survey it is hard to separate confounding factors - the big on in this case is people who smoke also eat what is considered a less healthy diet and so it is hard to figure if the diet is really less healthy, or just another bad effect of smoking.
That said, there is some good science out there. I don't know how to find it, but there are nutritionists who know statistics and are making real attempts to separate the above confounders to find a truth. They tend to not get a lot of press though: since most of what they discover is small effects it won't generate headlines, while someone who doesn't take care can easily cherry-pick something and extrapolate far beyond reason to claim another miracle diet that will add 10 years to your life (or something else that diet will never do)
My dream is one day we will reverse engineer the human body completely, no more mysteries with the ability to recreate any part of it seamlessly if it ages or is injured.
We know that vegetables are good for you. Processed food is not so good for you. We also know that eating too much causes problems.