https://en.wikipedia.org/wiki/Healthy_diet
Various nutrition guides are published by medical and governmental institutions to educate individuals on what they should be eating to be healthy.

Healthy dietary guidelines are similar:

• World Health Organization
• World Heart Federation
• World Cancer Research Fund
• American Heart Association
• American Institute for Cancer Research
• DASH
• Harvard School of Public Health, Harvard plate
• European Food Safety Authority
• British Dietetic Association
• British Heart Foundation
• British National Health Service
• Health Canada, Canada's food guide https://food-guide.canada.ca/en/
• Heart and Stroke Foundation of Canada

The consensus is that healthy diets contain mostly whole foods from plants:

• whole grains
• vegetables
• fruits

Healthy diets minimize:

• processed meat (nitrates)
• refined sugar (including drinks and juice)
• refined grain (white flour, white rice)
• dietary cholesterol (eggs)
• red meat (beef, pork, lamb)
• saturated fat (dairy, eggs, meat)

Most healthy diets do not require, but allow these foods in moderation:

• white meat (poultry, fish)
• low-fat dairy
• vegetable oil

Many healthy diets aren't really the healthiest. Rather they are a compromise between current dietary intakes and what experts believe is the healthiest diet.

https://nutritionfacts.org/video/how-to-treat-high-blood-pressure-with-diet/
The DASH diet was designed to contain enough animal products to make it palatable to the general public.

Preparation and use of food-based dietary guidelines, by Word Health Organization 1998
https://apps.who.int/iris/bitstream/handle/10665/42051/WHO_TRS_880.pdf page 12.
2.5 Reorientation from nutrients to foods in formulating food-based dietary guidelines.

• .. Even when public health problems exist (e.g. high rates of mortality from cardiovascular diseases) and a difference also exists between the numerical dietary goal (e.g. 10% energy from saturated fatty acids) and the prevailing intake of the target nutrient (e.g. 16-18% energy from saturated fatty acids as in northern Europe), the food based dietary guidelines (FBDGs) should be based on what can realistically be achieved in the socioeconomic context rather than on an attempt to eliminate in one step the entire difference between the desired and actual intakes.

WFPB does not try to guess what diet an individual can realistically achieve. WFPB guidelines simply specify the healthiest diet for humans:

• whole grains
• vegetables
• fruits

Any deviation from the healthiest diet is left to the discretion of the individual.

Most people that call themselves WFPB eaters do not eat 100% WFPB. They are not perfectionists. For practical or social reasons, they allow themselves to eat some non-WFPB food:

• restaurants
• invited to dinner
• convenience

The bulk of their diet is WFPB. For example, a 90% WFPB diet has a 10% allowance for non-WFPB food.

In practice, implementation of WFPB and main-stream healthy dietary guidelines can be similar. The difference is that WFPB guidelines actually describe the healthiest diet for humans.

Can we say what diet is best for health?
https://www.annualreviews.org/doi/full/10.1146/annurev-publhealth-032013-182351
Yes. The case that we should, indeed, eat true food, mostly plants, is all but incontrovertible. An important aspect of this message is that the same basic dietary pattern exerts favorable influences across a wide spectrum of health conditions.