The Science of Healthy Eating

Health | . Edited . 19 min read (4523 words).

There is a lot of confusion in the news and elsewhere about what food is healthy for us, but beyond the noise, public confusion, and fad diets there exists solid science by now. This post looks at what is actually healthy!



I read a lot and I have an interest in health for the same obvious reasons that others do. Over the years, I have read a lot of bad and confusing information about nutrition and health, to such an extent that I had concluded that it was all nonsense and my best bet was to just focus on exercise and sleep instead.

This all changed when I picked up Dr Michael Greger’s book How Not to Die this year and slowly started to realise how overwhelming the scientific evidence for the substantial health benefits of a quality diet is. In the coming months, I read up on everything I could find related to this and switched my diet over as I learned. I feel great on my new diet and, much more importantly, I am finally convinced that there is solid science for how to eat healthily. As someone who has been a vegetarian in the past, I feel at home with this, but the science behind it is what we should focus on in my opinion. I want to share all this with whoever reads this.

Naturally, the available scientific knowledge will improve further over time and I am looking forward to learning more as that happens.

I will give a quick overview here, but there is no need to take my word for any of this. In no way is this another fad diet based on some new ‘health guru’. The science is there and you can verify that yourself if you want. Let us get started!

The WFPB diet

The short answer to what we should eat for the best health benefits according to science is a whole-food plant-based (WFPB) diet. The rest of this section describes what that means. It is a vegan diet, but the two are not the same.

Eating a WFPB diet very conveniently summarises what current science has shown to be the most healthy foods to eat, but it is still a simplification and there are more aspects that can be taken into account.

This will describe the kind of WFPB diet that I eat and believe to be the healthiest based on my reading so far. Other variations exist. Another way to describe this diet would be to simply call it a ‘high-quality vegan diet’, but WFPB is the most widespread term.

Foods to avoid in a strict WFPB diet:

Foods that belong in a WFPB diet:

If we break WFPB down into its two parts, this becomes more apparent. Anything non-vegan fails the ‘plant-based’ part. Added salt is not from plants either. The other part is ‘whole-food’. This is where some vegan food fails to be WFPB: sugar, juices, oils, alcohol, processed foods, white flour, and so on.

One clarification is needed regarding ‘processed’: WFPB is not the same as eating only raw food. Dr Greger phrases this well: ‘think of “unprocessed” as nothing bad added, nothing good taken away’. Cooking is generally not a problem.

Another clarification is also in order. This ‘diet’ is not a ‘weight-loss diet’. It is simply a healthy way of eating, which you can benefit from for the rest of your life.

More specific details of a healthy diet (some very important) are described as sub-sections here. Further down, you will find explanations of the health benefits and the science behind this with plenty of references to other sources.

Vitamin B12

Vitamin B12 is essential for optimum health and a deficiency is very dangerous. Since animals also need B12, omnivores get some B12 from the animals they eat. Originally, B12 gets created by bacteria and we used to get it from dirt and water, but in modern water supplies we kill all bacteria (which is overall a good thing) and we no longer get B12 from a strict plant-based diet.

I recommend following the Vitamin B12 recommendations from Dr Greger, who also has videos where he explains the data behind those. Many omnivores can also benefit from supplementation based on what I have read.

I take 2,000 microgram cyanocobalamin once a week, which is cheap and reliable.

More information:

Omega 3

This remains an open research area, but some is already known. We get basic forms of omega 3 and other essential fats from plants in a WFPB diet and the body can create all the longer variants it needs from that. Whether it is best to supplement with more of the longer variants of omega 3 (DHA and EPA) using a vegan DHA supplement for optimal health still requires more research before we know for sure. Dr Greger and Dr Fuhrman currently recommend supplementing for now and others do not recommend it, including Dr Klaper.

What appears to be known:

Based on this, it makes sense to eat ground chia and flax and other healthy whole foods that contain ALA (e.g. walnuts) regardless. Based on the fact that people eating a WFPB diet have overall good health, it would be logical that no supplementation is needed with a high-quality plant-based diet. Everyone needs to make their own mind up on whether to supplement with DHA or not. If supplementing, it makes sense to do so from algae based supplements.

More information:

Other supplements

Apart from B12, you can in theory get everything you need from a WFPB diet. In general, whole foods are much better than supplements. There are still a few that are recommended, however. DHA has already been discussed above.

Dr Greger has a great summary page about this: Optimum Nutrient Recommendations.

Living in Sweden, I currently take these supplements:

Everything else, with a potential exception of DHA (see above), appears to be safer to get from food for most people. I no longer eat protein powder or creatine.


The number of health benefits from eating flaxseed are astounding. Eating one tablespoon of ground flaxseed a day (raw or cooked) is safe and healthy.

As always, Dr Greger has a lot of good information available: Flaxseed.

One thing to be aware of is that flaxseed contain cyanide. The Swedish Food Agency even recommends not eating raw ground flaxseed at all for this reason (in Swedish here). However, even the Swedish Food Agency, nowadays agree that 1-2 tablespoons of whole or 1 tablespoon of ground cooked with liquid per day is safe. As a Swede, this triggered me to read up on this.

It appears like there is good data supporting that:

Recommended videos from Dr Greger on this (with more sources):

These research papers are also worth reading:


Turmeric is a spice that has a lot of great health benefits. It is better absorbed if eaten with a little black pepper. The primary benefit is in lower inflammation, including muscle soreness from exercise.

Eating 1/4 teaspoon of turmeric with black pepper every day is all it takes to get additional health benefits from this. I usually add it to my morning oatmeal together with ground flaxseed (see above).

More information:

Green tea

Another healthy habit is to drink green tea between meals. It is even better (and more convenient) if you make it over night by putting for example 3-5 tea bags in cold water over night (3+ hours) in the fridge.

Dr Greger has more information here: green tea.


Eating antioxidants as a pill does not work, but eating antioxidant-rich whole foods is very healthy. Since the amount of antioxidants vary greatly, this is something that can be optimised even when you eat a WFPB diet by eating for example blueberries, walnuts, red apples, and clove.

The quickest way to learn more is to watch some of Dr Greger’s videos about antioxidants.


Eating unrefined foods with a lot of dietary fiber is very healthy in plenty of ways, including for your gut microbiota which has increasingly been shown to be important for overall health. This is not something you need to think much about on a WFPB diet, but it is another aspect that you can keep in mind to make healthy choices.

More information:


There are a lot of myths related to protein and plant-based food circulating. The resources linked further down give you complete background on all of this.

The short version of this is that all plants contain protein, including all essential amino acids. By simply eating a WFPB diet, you will get protein.

One of the myths that I had heard about before was that of ‘incomplete protein’. I used to believe that I had to combine different kinds of vegan foods (beans and whole grains or similar) to get ‘complete protein’. After looking into this, it upsets me how wrong this is. As with most things, there is a grain of truth in this, but not more than that.

Since I like oats, I looked up the amino acids contents of oats (from different sources). It has ‘incomplete’ or ‘low-quality’ protein because it has a lower amount of lysine than the other essential amino acids (compared to RDI). Why is that important? It isn’t. All it means is that you need to eat 300g of oats (7.5dl) if you want your whole recommended daily intake from oats alone. According to this page, you would then get 100% RDI of lysine. At the same time, you would get >200% RDI of several of the other amino acids, which is arguably a waste then.

There are several reasons why this is nothing to worry about:

  1. You still get enough of all the essential amino acids, even if some of the protein is ‘wasted’ by having unbalanced amounts of the amino acids.
  2. A varied WFPB diet will contain plants with different amino acid profiles.
  3. This might even be one reason why plant-based protein is more healthy.


It appears like many people are worried about getting iron deficient on a plant-based diet. Here, again, plant-based sources of iron instead seem to be the safest and most healthy ones, if you disregard popular opinion and look at the science. That said, it is surely possible to get deficient for some individuals regardless of diet, so if you are at risk, read up on this.

Dr Greger has more information here: Iron.


If you eat a WFPB diet without (or with little) salt, how do you get enough sodium? This was something I wondered until I realised that all plants contain sodium. My conclusion is that you get what you need (and not much more) from simply eating WFPB. Not eating added salt has several benefits, such as lowering the risk of high blood pressure.

Daily dozen

Different categories of food contain different nutrients. Some variation is therefore good. I really like the daily dozen guide that Dr Greger has created to simplify this. Get the smartphone app and try to eat from all categories most days.

Health benefits and research

The best thing about eating a healthy WFPB diet is that it helps prevent most if not all diseases at the same time. From an evolutionary perspective this makes sense. Naturally, we can eat one diet and stay healthy overall and this turns out to be such a diet.

I included links and quotes for research that I found by some quick searching online. I included what I found, with a focus on recent open-access reviews that I found trustworthy. Some of the research is inconclusive as there are open research problems still. I trust Nature (and related journals), so I was happy to find a lot published there. Keep in mind that some of the research below refers to vegan diets and not all vegans eat healthily.

I encourage anyone who is suspicious about whether the science behind this is for real or not to read up on their own. A good thing about facts and science is that there is no need to take anyone’s word for it.

Body weight

Let us start with weight, since this appears to be a strong motivator for many.

By simply eating as much as you want of a WFPB diet, you will typically reach a healthy weight. It is that simple. Having gained some weight through the pandemic myself, I can attest to this in myself and everyone I know who have tried this. More importantly, this shows up in research too.

No need to count calories. Just eat until you are not hungry. The risk of getting severe cravings for vegetables and overeating are slim to say the least. On the other hand, keep in mind that you do need to eat plenty on a WFPB diet so do not try to starve yourself - there is no need anyway.

Sounds too good to be true? It does, but there is research on this. Some research is linked below and more can be found by searching online.

Some research with quotes:

Reduced inflammation

Inflammation serves a purpose when it is needed, but chronic inflammation is a risk factor for many diseases. A WFPB diet decreases inflammation.

Research reviews:

Cardiovascular disease

A WFPB diet lowers the risk of cardiovascular disease.

Research reviews:


A WFPB diet lowers the risk of cancer too.

Research reviews:

Mental health

The evidence is more inconclusive here, but it potentially helps. This is one area where a WFPB diet seems to be better than eating a vegan non-WFPB diet.


Brain health

It appears that a WFPB diet slows cognitive decline when getting older and promotes brain health. More research is needed.


There are a lot of news articles about choline from 2019 claiming that vegan diets are damaging your brain. The Physicians Committee in USA clears this up here. This appears to be a typical case of someone with egg and meat industry ties spreading claims that stir up confusion without being backed by any science. Choline is found in lots of plant foods.

Overall health

Since a WFPB diet is healthy overall, let’s look at the overall effects too.


Other diets

For completeness, here are some quick comments about other diets.

Veganism and vegetarianism

These are some of the most similar diets to the above WFPB diet and a WFPB diet is in fact fully compatible with them (but not the other way around). Not all vegans and vegetarians choose to eat as healthily, however. WFPB is a stricter diet that is more strongly focused on healthy eating.

Most of the advantages of veganism and vegetarianism are shared with WFPB, such as being friendly to the environment and not hurting animals. An advantage (in taste) with these two other diets is, of course, that they contain more choices such as processed foods with sugar and fat. It is also much easier to find vegan and vegetarian alternatives when eating out, so I usually go with a vegan option then.

Low-carb diets

These diets are essentially the opposite of a WFPB diet and all the science behind a WFPB diet also indirectly discredits the health claims of these diets. Read the recommended books below for much more on this.

These are the best and most practical books that I read about this type of diet:

Michael Greger’s two books also have accompanying cookbooks.

Other good books that I read about the science behind nutrition and WFPB:

Online resources

Here are some good online resources for learning more: