Media playback is unsupported on your device Media caption Roti Bank in India and FoodBlessed in Lebanon get food to those in need (video available to international viewers only)

Up to one third of the world's food is wasted before it can be eaten. That's 1.3 billion tonnes, according to the Food and Agriculture Organization of the United Nations.

At the same time up to 793 million people don't get enough nourishment to help them live a healthy life. So, what can be done to fix these two major challenges the world is facing?

In India, dabbawalas are using their world-renowned delivery techniques to pass on surplus wedding food to the poor, as Matthew Wheeler and Priti Gupta found out, while in Lebanon, FoodBlessed's "hunger heroes" showed Carolina Valladares and Mohamad Chreyteh their food rescue techniques.

The 'Dabbawala Roti Bank', India

Image caption The Roti Bank says it could help more people if it had somewhere to store all the food

In Tardeo, in south Mumbai, there is a wedding party taking place, with hundreds of guests working their way through mountains of delicious food.

But some guests here are not eating. They are dabbawalas. And although they're off duty, as it's a Saturday afternoon, they are wearing their bright white uniforms and are about to do the job they do best.

Unlike the regular paid work they do during the week (when they collect, transport and deliver countless lunchboxes to office workers all over the city), today these dabbawalas are delivering food to Mumbai's poor. As soon as the wedding guests have had their fill, the dabbawalas will take all the food that hasn't been served, pack it up and get it to a nearby street where homeless people are living rough.

This is the dabbawala's "Roti Bank" in action. Founded six months' ago by Subhash Talekar, the Roti Bank makes use of the legendary food delivery skills of the dabbawalas to solve the twin problems of hunger and food waste. It's a simple idea that Mr Talekar sums up neatly: "We collect excess food from parties and distribute it in slum areas where people have no food to eat."

Another guest at this wedding is Rushikesh Kadam, along with his team of 20 volunteers from his Food For All campaign. His research has shown that, on average, a Mumbai wedding wastes the equivalent of 50 meals.

It's an appalling statistic, especially when you consider that, across India, one child in every four is malnourished. So, like Mr Talekar, Mr Kadam is on a mission to eliminate food wastage and, whenever possible, the two organisations are collaborating.

Sharing economy

"They know where the underprivileged and needy people are in Mumbai," Mr Kadam says. "People get our number from the internet, they contact us and then the dabbawalas who live around that area get a call from the HQ. They then collect and deliver to the needy or underprivileged."

News of the Roti Bank initiative has spread rapidly and more and more wedding planners and party organisers are getting in touch every month.

Image caption Indian weddings often have surplus food which the dabbawalas are now handing out to the poor

"We have around 5,000 dabbawalas," Mr Talekar says. "And 400 are part of Roti Bank. The difficulty we face is we can only manage to feed 200-300 people per day. The challenge is how to store the food given to us. By the time we get food it's one in the morning sometimes. So it becomes difficult to distribute food so late. If we had a storage facility we would be able to feed many more."

As he and his team distribute the excess party food to dozens of homeless people about a mile from the ongoing wedding celebrations, Mr Talekar explains how the next stage for the Roti Bank is to get his food-sharing message into homes and offices.

"Now we are telling our tiffin customers that even if food for just two people is left over, do not throw it away. Dabbawalas are available at every railway station in Mumbai - so give the leftover food to them.

"We will give that food to someone who is hungry."

Changing the Rules

How social entrepreneurs are tackling the world's problems

Special Report: Changing the Rules

FloodBlessed, Lebanon

Image caption FoodBlessed has been in operation for four years

Food waste in Lebanon is a big problem.

But it's one that Maya Terro, co-founder of FoodBlessed, a Lebanese organisation that tackles food poverty while spreading awareness on food rescue, hopes to change.

"I felt paralysed by the fact that while lots of food is going to waste every day, there are many who aren't able to afford a meal. A lot of food that is fine to consume ends up being considered as wasted goods but it is not - because you can still eat it," she says.

FoodBlessed was founded in 2012 after the Syrian refugee crisis started. Today, Lebanon is the home to more than 1.5 million Syrian refugees. And with nearly 29% of the Lebanese population living under the poverty line, that's a lot of mouths to feed.

In these four years FoodBlessed has served 260,000 free meals made with the extra food to the needy, saving hundreds of tonnes from ending up in the rubbish.

Future plans

"How do we do it? We link food donor companies or restaurants with surplus meals with the individuals we think are in need," Ms Terro says.

They are currently serving up 400 meals a week to people who come to their three different soup kitchens. But this is just the beginning.

Image caption The FoodBlessed volunteer numbers have grown considerably

They are now planning to buy a truck to reach those who cannot come to them.

"People ask us if we help everyone, and yes, we do. We help the homeless, people who have lost their families and of course refugees," Ms Terro adds.

Nearly 900 volunteers pick up the food from supermarkets and restaurants and prepare the meals. Ms Terro calls them "hunger heroes" because "even though they don't have superpowers they are everyday heroes".

Ms Terro believes FoodBlessed can make a difference.

"We are setting a new way of doing things here in Lebanon," she says.