From black bean burgers on restaurant menus to eight varieties of hummus at the supermarket, the meatless movement shows no signs of slowing down.

The first real blip of vegetarianism in the United States started in 1971 when Frances Moore Lappé published Diet for a Small Planet, and explained that meat-based diets can be harmful for our planet and our health. Lappé wrote about ways to reduce food waste and enhance sustainability, but her ideas weren't widely acted upon; she was ahead of her time.

Becoming a flexitarian will also have health benefits. Credit:Getty

Fast-forward 45 years, and these same issues routinely make headline news as worries about our food supply escalate. Lappé's ideas are now being recycled as a new wave of concerned citizens, especially millennials, turn to meat-free eating for better health - both for ourselves and the planet. But this time, the momentum may be strong enough to make some changes.

Lappé was only 27 when she wrote Diet for a Small Planet. If you're 27 these days, you're considered a millennial, the generation known for being socially aware, civic-minded and environmentally conscious. Their buying power is affecting what we see on restaurant menus and in supermarkets.