LONDON: Just days after registering his name in the Guinness World Record as the oldest person to complete a marathon, 100-year-old Fauja Singh has now become the oldest man to star in a PETA ad campaign.Singh, who made headlines around the world after completing the Toronto Waterfront Marathon on Sunday, has joined the ranks of celebrities such as Sir Paul McCartney and Alicia Silverstone by appearing in the "I Am a Vegetarian" ad series started by PETA (People for the Ethical Treatment of Animals) US.The ad features him mid-stride and reads, "I am Fauja Singh, and I Am a Vegetarian. 100-Year-Young Marathon Runner and World Record holder".Singh is part of a long list of celebrities, including Bryan Adams , Casey Affleck , Forest Whitaker , Shahid Kapoor , Lara Dutta and R Madhavan, who have teamed up with PETA India or its international affiliates to promote a vegetarian diet.Singh, who rediscovered his passion for distance running at age of 81, credits his vegetarian diet for his stamina and longevity."You need a balanced and wholesome diet. It doesn't matter how nice to look at or sweet food is -- if your body can't digest it, why eat it?" asked Singh."In many parts of the world, people are dying because of starvation, whilst others are dying because of overeating. My solution is just to eat what my body needs," he said.Eating animal products has been conclusively linked to heart disease, diabetes, strokes, obesity and cancer. Vegans and vegetarians are much fitter and trimmer, on an average, than meat-eaters are."Fauja's vitality is an inspiring demonstration of the positive effects that a vegetarian diet can have on our physical and mental well-being", says PETA nutritionist Bhuvaneshwari Gupta."A meat-free diet not only reduces our chances of developing life-threatening illnesses but also, as Fauja demonstrates, helps us to live longer," he added.