I think it’s important to start with me saying that I hate the ‘unhealthy’ vs ‘healthy’ debate when it comes to food. Good vs Bad is a natural human bias, but it tends to create a bit of a toxic food environment. It hurts our relationship with food and increases confusion about nutrition, rather than enhancing it.
Healthy or unhealthy, is entirely context, and dosage dependent.
As I’ll detail in my answer, some cruciferous vegetables, by and large, are very healthy for the majority of people. However, they can become unhealthy in people with selenium or iodine deficiency and other thyroid-related disorders.
Likewise, even something we all generally demonize, ‘sugar,’ can be very useful in the context of recovery from intense physical activity. It can also increase performance in long-duration endurance performance as well. For most people, a diet high in sugar certainly isn’t a very good idea, but it can have its place for particular objectives.
Juice, is easily over-consumed, but in small manageable doses could also have a place in your diet, and many have been shown to have positive health effects too.
Yogurt, in its plain form, is also generally considered healthy. However, take a look at the grocery store selection and you’ll see that the majority of people opt for sugar-laden alternatives (generally you’ll see as high as 20:1 selection of sweetened versions to plain versions).
How you treat your food is important and marketing is generally in place to make you eat more than an ideal quantity of food overall. Provided you can manage ideal dosages, most foods are not 100% bad for you (the only real exception I can think of, off the top of my head is hydrogenated trans-fatty acids found in many processed vegetable fats — and even then, some ingestion won’t kill you), nor 100% good for you.
If you tried to eat every single item of food ever quoted in a study, as having positive health benefits, in quantities that have been shown to have those benefits, every single day, you’d no doubt be well beyond your needed energy intake, despite the high quality of your food.
You can’t do it all, eat EVERYTHING that’s ‘healthy’ and avoid EVERYTHING that is ‘unhealthy.’
This will still most likely lead to weight gain and the detrimental health effects that are generally associated with obesity (like diabetes, CVD, etc…). This is despite having what most people could, or might consider a ‘healthy’ diet. Overall quantity still matters even for research ‘proven’ healthful foods.
You can still overeat foods that many of us associated with ‘health,’ it’s just less likely because they are generally harder to overconsume. Whether they are full of more fiber, or protein, high water content, or are more satiating in general, we have a harder time eating too much of them in their less altered states.
Fat-Free (typically = loaded with simple sugars instead)
“All-Natural” or “Made from Natural Ingredients” (as if natural prevented Lead or Mercury from being very toxic)
“Organic” and yet, still processed into a box or packaged (not ALWAYS but very often)
Juice (especially types that have sugar added and are not 100% juice, these often get counted as a serving of ‘fruit’ or ‘vegetables,’ in my opinion – mistakenly)
Most breakfast cereals (throw a bunch of heavily processed grains and ingredients together, market it as ‘healthy’ like Special K, ya right….)
Yogurt (if we’re talking plain, high protein versions, OK maybe, but most people opt for types with a ton of added sugar – see ‘Fat-Free’ above too)
Dried Fruit (in small quantities sure, but I’ve known plenty of clients who go to town on these and they are very energy dense, particularly in sugars, making them easy to overeat – a small cupped hand is generally 1 serving)
Bread (think something like Ezekiel bread) can still have a healthy place in your diet, and by all accounts is fairly processed overall (ground flour, salt, water, yeast, mixed together and baked). It’s the extremely processed stuff that I think most people should generally avoid (though having some from time to time, probably not a HUGE deal breaker either). Here might be another example of where context is also important, gluten-full bread is very unhealthy to the celiac but mostly fine for everyone else.
Other examples of food of this nature may include:
Cheese (especially Raw, and/or minimally processed varieties) – could be potentially healthful (dairy consumption is positively correlated to maintaining a healthy weight)
Yogurt/Kefir (provided it is plain) (again, dairy, but also some fermented products improve gastrointestinal healthy in some people too)
100% Juice or Juice you make yourself (easy to over-consume because it’s a liquid, but certainly a glass a few times a week for most people won’t break the bank if they so chose)
Dried fruit (provided they are consumed in appropriate quantity – i.e. sparingly and perhaps the preservative free types are generally better – if you look at dried cranberries, you’ll often see added sugar and sunflower oil…what?)
Hamburgers you’ve made yourself with minimal ingredients from high-quality sources in particular (I make burgers all the time, but avoid the caloric bombs by using leaner chuck and skipping the buns and heavy sauces)
Many homemade/minimally processed soups (which are ‘processed’ look on the labels of some canned soups)
Many raw vegetables are great for you, while simply cooking others negates 1/3 of any goitrogenic effects (I’m not personally a fan of all raw diets, but to each their own I suppose, cooking can often make many great vitamins and nutrients more bioavailable).
Many protein powders (extremely processed when you think about it, I look for ones with ingredients like 3-4 ingredients whey, vanilla, cocoa, and stevia only, but very useful for people who are very physically active)
Eat manageable quantities and there is most likely no appreciable health detriment of certain foods, but nearly everything and anything can be over consumed if you put a lot of effort forth. It’s just generally harder to over-consume whole minimally processed foods in general because they require a lot more from us digestively speaking. They leave us feeling full for longer and are more difficult to breakdown/process.