https://en.wikipedia.org/wiki/Western_pattern_diet
Based on epidemiological studies, compared to a healthy diet, the Western pattern diet is positively correlated with an elevated incidence of obesity, death from heart disease, cancer (especially colon cancer), and other "Western pattern diet"-related diseases. There is an evolutionary mismatch between the ancient physiology of humans and a Western pattern diet; this underlies diseases of civilization, which include Type II diabetes, epithelial cell cancers, autoimmune disease, osteoporosis, hypertension, coronary artery disease, and obesity. There is also a correlation between a Western pattern diet and an increase in inflammatory diseases, which is particularly evident in relation to fiber and fat-content.

Multiple Chronic Conditions in the United States (2014 data) by RAND Corporation
https://www.rand.org/content/dam/rand/pubs/tools/TL200/TL221/RAND_TL221.pdf

• Figure 1.2. Prevalence of Multiple Chronic Conditions, by Age (2008–2014)
  • 18% of 18-44 year olds have multiple-chronic conditions.
  • 50% of 45-64 year olds have multiple-chronic conditions.
  • 81% of over 65 year olds have multiple-conditions.
• Figure 1.5. Prevalence of Top Chronic Conditions, 2014 [most of these conditions can be reversed with a WFPB diet]
  • 27.0% Hypertension
  • 21.6% Lipid disorders (e.g. high cholesterol)
  • 11.9% Mood disorders
  • 10.4% Diabetes mellitus
  • 9.7% Anxiety disorders
  • 7.4% Other upper respiratory disorders
  • 7.4% Inflammatory joint disorders (other than arthritis)
  • 6.5% Osteoarthritis
  • 6.3% Asthma
  • 4.8% Coronary atherosclerosis and other heart disease

Multiple Chronic Conditions Chartbook by Agency for Healthcare Research and Quality
https://www.ahrq.gov/sites/default/files/wysiwyg/professionals/prevention-chronic-care/decision/mcc/mccchartbook.pdf
Page 6, Most Prevalent Chronic Conditions in Adults (18 and older) – 2010

https://www.ncoa.org/resources/10-common-chronic-conditions-adults-65/

Cardiovascular diseases and cancer are the leading causes of death.

Numbers for causes of deaths per year:

• https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm
• https://en.wikipedia.org/wiki/List_of_causes_of_death_by_rate
• https://www.who.int/chp/chronic_disease_report/media/Factsheet1.pdf