Denny put natural foods on the map in Philadelphia in 1969 when he opened Essene, one of America's first natural food stores. Essene has flourished and shopping there remains an essential part of the natural food lifestyle in Philadelphia.
In 1982, Denny gained international recognition when he helped Dr. Anthony Sattilaro recover from terminal prostate cancer. This experience is documented in Dr. Sattilaro's book entitled, "Recalled By Life".
From 1976 - 1985, Denny ran the Mid-Atlantic Summer Camp that was attended by more than 600 individuals each year. At the Summer Camp, lectures, cooking classes and children's programs provided a wide-range of macrobiotic educational activities.
Denny has established himself internationally by traveling and living in Europe and Asia. As Director of the Kushi Institute and the Community Health Foundation in London, Denny led the development of public and professional educational programs in Oriental diagnosis and macrobiotics and oversaw the organization's health counseling center. Working
with the Polish government, Denny helped to create policies to address the rapid development of AIDS in that country.
In 2002, Denny founded The Strengthening Health Institute to integrate his teaching with the work of other like-minded macrobiotic teachers into an independent non-profit organization. The Strengthening Health Institute offers a variety of educational programs including weeklong intensives and a comprehensive certificate program in macrobiotic studies.
After writing numerous health-related articles in various journals and publications, Denny published his first book, "10 Steps to Strengthening Health" with Ruth Ann Flynn in 1997. In 2002 he published “The Great Life Handbook” and is currently working on his third book “The Power of Foods”. In 2005 Denny received the Aveline Kushi Award in recognition of his long term service to Macrobiotics.
Denny maintains an active health counseling practice in Philadelphia and New York City. Through these practices,
he guides people with a variety of health concerns, ranging from allergies to cancer, to regain their health through a natural approach to lifestyle and diet.