Dr. Michael Greger

Dr. (MD) Michael Greger is a popular medical figure in the plant-based healthful-eating community, being one of the biggest influencers for a purely whole foods plant-based diet.
Michael Greger is likely to be the most widely-known advocate for a WFPB (whole foods plant-based) diet.
The main outreach platforms he uses are his Youtube channel and his website Nutritionfacts.org.

Positive impact

Popular outreach videos

While Dr. Greger had posted videos since early 2011, it was not until mid 2012 that a video he posted really put him on the map of Youtube.
After more than a year of series of many short videos talking about specific things directly to the point, he uploaded a speech he had given, titled 'Uprooting the Leading Causes of Death' (currently 1.8M views). In the video, Greger talks for almost an hour in a well-delivering way about how the consumption of animal products significantly worsens the health outlook in almost all the most common causes of death, with a WFPB diet preventing and even, in certain cases, reversing such causes. He goes through each main cause of death systematically providing evidence and multiple studies, showing that eating animal products seriously increase all-cause mortality.
The video made a big impact in changing a lot of minds, and is used and shared even today (2021).

He followed this speech with other similar talks, like the one in 2013 'More Than an Apple a Day: Preventing Our Most Common Diseases' (400K views) and the one in 2016 'How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers' (780K views).

Other popular videos in the beginning of his Youtube work that caused him to gain a significant outreach include 'Eggs and Diabetes' (1.3M views), 'Does Coconut Oil Clog Arteries?' (1.1M views), 'Who Shouldn't Consume Curcumin or Turmeric?' (1.6M views), and other less controversial videos such 'Canned Beans or Cooked Beans?' (1.3M views).

When it comes to videos that did not necessarily put him on the map (posted later on when he had already gained a significant following) but that still gained vast popularity, he has important and impactful work such as 'How Our Gut Bacteria Can Use Eggs to Accelerate Cancer' (1.7M views), 'Egg Industry Response to Choline and TMAO' (700K views) and 'The best diet for diabetes' (1.4M views) - three examples of many of the videos he has that make really strong cases in favor of a WFPB diet.

One think to note about Greger is that his videos are rarely redundant with previously widely-known nutritional evidence, and instead bring to the table some of the latest work and research in the medical world. This is probably one of the factors that set him ahead compared to other health-related Youtube channels.

Other popular videos include 'Chocolate and Stroke Risk' (2.4M views), and 'Eat More Calories in the Morning to Lose Weight' (900K views).

Considering the amount of popular videos he made and the fact that his channel has 150M total views (2021), there is little doubt that he reached tens of millions of different people and made an incredible impact in the health-related community by strongly pushing towards a vegan (WFPB) diet with thousands of studies and meta-analysis, and hundreds of thousands of hours of collective work from him and his team of researchers (non-profit and volunteers).

Controversies and unscientific stances

Bias towards excessive amounts of fruits being good

https://www.youtube.com/watch?v=nU_RkeA88DY

- Greger does not talk about how there are significant nutritional diminishing returns to eating many fruits, and instead focuses only on the positive aspects with things such as fiber intake and ORAC value total amount, and using data from studies that look at, for example, 17 people only, and how they improved eating a lot of fruits from a bad diet (instead of looking at a non-high-fruit WFPB diet, vs. a high-fruit WFPB diet, which would be a fair comparison and a good way to understand whether fruits are actually good - such studies may not exist, but then it cannot be claimed that there are no downsides to eating fruits in large quantities).

- Greger ignores the fact that fruits are not the best 'bang for the bucks' in terms on nutrients for amount of calories, and as soon as getting what is needed from fruits (micronutrients and ORAC value not too far down the diminishing return scale) is done, it is a waste of calories to spend more of the remaining daily calories in your diet eating fruits rather than something magnitudes more nutritionally dense.

- Greger does not acknowledge that sugar in fruits causes dental problems, relying on:
1. weak evidence that polyphenolic compounds in fruits may in a significant way reduce bacterial growth rate and bacterial adherence to tooth surface (therefore less cavities)
2. the protection that fiber and water found in fruits offer to the teeth, from the sugar in fruits (fiber and water enclosing a part of the sugars, thus those sugars not going into contact with teeth, therefore less cavities) - even though that protection is weak and a part of the sugars still does come in contact with teeth (therefore the more fruits, the more sugar comes into contact with teeth, the more cavities) -

and uses those as assurance that the worry becomes negligible regardless of the amount of fruits eaten (when it should clearly be a worry, since there is good reason to believe that also the sugars found in fruits would increase the amount of cavities, and no good reason to believe the contrary).