What can the food we don’t serve teach us?

A trillion-dollar problem hiding in plain sight

While researching global sustainability challenges, one issue stood out to Marc: food waste.

“It was a trillion-dollar problem that was being virtually ignored,” he says.

That realization inspired him to create Winnow, a company dedicated to helping chefs and kitchen teams understand what’s ending up in the bin and how to prevent it.

“Food is life. There’s a lot that goes into this, and I think we should love food and not throw it away.”

Giving leftovers a voice

Using cameras, scales and AI-powered technology, Winnow helps kitchens identify and measure food waste, turning what was once guesswork into actionable insights and actions.

“When you give the right data and information to chefs, and you help them make better production decisions, you can dramatically cut food waste.”

The technology helps kitchens answer simple but powerful questions: Are we preparing too much food? Are ingredients being fully used? Can we plan tomorrow better than what we did today?

Better for business, better for the planet

Food waste isn’t just an environmental challenge. It’s also a business challenge.

“There’s over USD 1 trillion a year lost through food that’s thrown away. For businesses, it’s less profit. It’s lost margin. So it’s kind of a win-win to get after it.”

That’s why organisations around the world, including IKEA, are using data to better understand where waste happens and how it can be reduced.

Last year, Winnow passed an important milestone: kitchens using its technology around the world are now saving over USD 100 million in food waste every year. Their next goal? Save the hospitality industry USD 1 billion.

Small actions. Big impact.

For Marc, tackling food waste isn’t about one big breakthrough.

“Reducing food waste is really about daily discipline and operations management.”

Whether you’re running a commercial kitchen or eating yesterday’s leftovers for lunch, small actions can add up to meaningful change.

Because when we start paying attention to what’s ending up in the bin, we often discover something valuable:

The best meal isn’t the one that’s prepared. It’s the one that’s eaten.

Listen to the latest episode of Screw It to hear how Winnow is helping kitchens around the world waste less food and make more of every ingredient.

Screw It – Episode 19 – Full Conversation Transcript

Katarina: Welcome to Screw It. Today I’m joined by Marc Zornes, the founder of Winnow, a food waste technology company helping restaurants across the world reduce food waste. Enjoy the episode! Marc, thank you so much for joining me. Tell me a little bit about yourself. How did you end up starting a food waste technology company called Winnow?

Marc: I think I have had two themes throughout my life: food and sustainability. I worked for the largest food wholesaler in the United States, which gave me a real understanding of operations. I helped run a warehouse for the company, but I was looking for more purpose. I then joined the U.S. Green Building Council, helping to roll out the LEED programme for retail. That was where the environmental movement and sustainability really clicked for me. While I was there, McKinsey released work on greenhouse gas abatement cost curves that was changing how Washington talked about the issue. I decided to work for McKinsey and become more involved in that area. I went back to school and eventually joined McKinsey in London. I quickly realised that there were around 500 consultants who wanted to work in sustainability, but only about five sustainability projects available. So I did more work in food, earned my stripes and helped write a McKinsey Global Institute report called Resource Revolution. We were looking at major changes in commodity prices, thinking beyond carbon and considering natural resources more broadly. Food waste emerged as an enormous problem: a roughly $1 trillion problem that was largely being ignored. It struck me as something that needed a solution—or, more accurately, many solutions—and that we would need to focus on it for decades to come. I tried to understand why there was food waste in the McKinsey staff restaurant and built a simple tool to track it. That led to Winnow, which now works globally to help prevent food waste in the hospitality industry.

Katarina: Why should people care about food waste?

Marc: There are many reasons, but I would boil it down to three. First, there is the environmental impact. If food waste were a country, it would be the third-largest greenhouse gas emitter in the world. We waste about one-third of all the food we grow, which accounts for roughly 10% of global greenhouse gas emissions. There is also an economic case. More than $1 trillion worth of food is lost or thrown away each year. For businesses involved in growing, shipping or selling food, that means less profit and lower margins. Reducing food waste is a win-win. Finally, there is a moral case. Food is life. A great deal goes into producing it, and we should value food rather than throw it away.

Katarina: When you started Winnow, it was a manual waste-tracking system, before computer vision was ready. Can you talk me through that journey?

Marc: When I first started Winnow, we were trying two versions of the technology. One was a simple touchscreen interface that I built to track food waste in the staff restaurant. The other was a motion-sensor camera designed to capture food as it was thrown away. We were trying to use computer vision to solve the problem. I spoke to experts around London, and in 2013 they told me we were well ahead of what the technology could do. But we knew we had something worth building on. When we measured food waste in the staff restaurant, the information we provided and the changes we made helped cut waste by 70%. It became clear that when chefs have the right data and information, they can make better production decisions and dramatically reduce food waste. The challenge was building the end product I had in mind before the technology was ready. We therefore built Winnow as a touchscreen interface because that was technologically feasible. The system grew to hundreds of locations, including IKEA. It worked when there was strong engagement, but there was still friction in the process. Around 2017, computer vision advanced significantly. We began building Winnow Vision, our current computer-vision technology, and launched it into the market in 2018 and 2019.

Katarina: If I own a restaurant and have a food waste problem, what is the process when I come to Winnow?

Marc: The first thing we try to do is put chefs and kitchen operations at the centre of how we think. Chefs have incredibly demanding jobs and manage a huge amount of complexity. They have ingredients coming in and need to produce many different dishes under time pressure. We want to be a tool that helps them, not an administrative burden. We start by understanding the operation and seeing whether we can help. Volume is one of the key factors, particularly the amount of food a site purchases. Once a business signs up, we are largely plug-and-play. We understand what it serves, configure the system and ship a device. The device is installed wherever food is thrown away. It includes a camera above the bin, a screen interface and a scale underneath. As food is discarded, the scale captures its weight and computer vision identifies what has been wasted. Kitchen teams do not need to engage with the system manually. We provide information in the kitchen about what is being thrown away and what the issues are, helping to raise awareness. After a couple of weeks, we give the business a detailed report showing what is being wasted and where it is coming from. It might be food that was purchased but not rotated correctly, or food that was cooked but not sold. We then use our tools to identify what the team can do differently. Usually within the first 100 days, chefs become comfortable using the data to understand what is happening in the kitchen. We generally reduce food waste by around 20% in those first 100 days. Over the longer term, we can reduce it by between 40% and 70% by value.

Katarina: What does the longer-term relationship look like? What makes people stay with Winnow?

Marc: We bring several tools to bear. First, we help businesses make the right amount of food at the right time. In large kitchens, food waste is rarely caused by one person. The executive chef may not have the time, capacity or visibility to see everything happening in the kitchen. We provide visibility and measurement for a problem that was previously difficult to measure. Some kitchens come to us after trying to record waste manually and realising they need a seamless solution. Other kitchens were not measuring food waste at all because it is time-consuming. At the beginning, there are usually some obvious opportunities. But reducing food waste over time is about daily discipline and operational management. It means understanding how menu changes affect demand, fully using ingredients from root to stock, and ensuring the team communicates effectively so that one decision does not create an error that costs the business. It also involves menu engineering. We do not try to make one big change. We identify the items with the clearest solutions, make small changes, test whether they have an effect and then move to the next opportunity. Because staff, menus and guest expectations change, reducing food waste is a continuous process.

Katarina: There is an environmental incentive to prevent food waste, but there is also a financial benefit. What do the numbers look like?

Marc: Globally, more than $1 trillion worth of food is wasted each year. In hospitality alone, the figure is well above $100 billion. When we work with clients, we can generally help them save between 2% and 8% of what they spend on food, which is significant for a business spending hundreds of thousands of dollars a year. The most important metric we track is what we call our North Star: how much food waste we prevent. I like that metric because it captures both the money we save for clients and the environmental impact we create. The bigger we make that number, the greater the impact and the more successful we will be as a business. At the end of last year, our customers were saving more than $100 million worth of food from being thrown away each year. In terms of meals, that is roughly two to three meals not being wasted every second. Our goal over the next few years is to grow that to $1 billion worth of food saved from waste annually.

Katarina: You have written that AI is a genuine accelerant when it comes to tackling food waste. Can you explain that?

Marc: There are several areas. The first is computer vision, which lets kitchens understand their food waste without requiring manual labour. Simply installing the system has helped drive adoption and growth, while also producing more accurate data. AI can then analyse that data and provide insights. We are increasingly using it to help customers understand what is happening in their kitchens.

AI also allows us to build tools faster—tools that can see and think on behalf of the kitchen team. That enables chefs to focus on what they want to do: cook creatively and make delicious food. At the same time, the technology can help them understand what is being wasted, what is being consumed and what guests want.

Katarina: Looking at the whole food system, where does food waste happen and who is responsible?

Marc: It is a large and complex problem that occurs throughout the food system. The reasons also vary by geography. At farm level in advanced economies, food may be grown but not harvested because it does not meet quality, size or shape specifications. Some of this is driven by relationships with customers and consumer preferences. There are also structural issues. Some machines used to process food only accept certain sizes, which limits what can enter the system. Bumper crops can create another challenge when there is too much of one product to distribute effectively. In advanced economies, there is not necessarily much waste in distribution because cold chains, logistics and technology are relatively strong. In developing markets, limited infrastructure can cause significant losses through poor storage and weak cold chains. This is a major infrastructure opportunity, and some companies are developing affordable cold-storage technologies that could help different parts of the world leapfrog existing systems. Food waste also occurs in grocery stores and restaurants. In the United States, consumer-facing businesses are one of the highest-value areas of food waste outside the home. Winnow is part of the solution, but there are many other tools and approaches being developed. Finally, there is food waste at home. People buy too much and cook too much. Overall, the issue involves getting food to where it is needed, reducing inefficiencies in distribution, balancing availability against abundance and using technology to make better decisions. It is a multifaceted problem.

Katarina: Why is food waste particularly high in the United States?

Marc: I think the United States has a strong cultural preference for abundance. It is also somewhat structural because the industry has operated that way for a long time. Consumer-facing businesses in most parts of the world generate a reasonable amount of waste, but the U.S. may have been slower to change than Europe. There is now momentum, including through organisations working on food waste in the United States. The issue is not unique to the U.S.; it is simply the market where I have the clearest data on the scale of the opportunity.

Katarina: What role does—and should—government and regulation play?

Marc: It is a very important question. In the European Union, there is a mandate to reduce food waste by 30%, and the way that target will translate into national requirements is still developing. In Spain, for example, large businesses are being required to have food waste prevention plans. That is sensible legislation. Many studies show that every dollar or euro invested in reducing food waste pays back multiple times, so it makes economic sense. We are not becoming less competitive by reducing waste; we are becoming more competitive. The question is why regulation is needed if the economics are so strong. I think it is about the speed of change. We may be able to reduce food waste by 30%, but without regulatory support I have low confidence that we will achieve it at the scale and speed required. Regulation can require businesses that produce large amounts of food to measure and understand their waste. Measurement is the first step towards reducing it.

Katarina: There is also work to be done on date labels. Many people see an expiration date and assume food cannot be eaten. How big a problem is that?

Marc: I think we have gone further than necessary with date labels. They are useful for understanding freshness and when food was produced, but we have moved away from using our own senses to judge whether something is safe to eat. Emily Broad Leib at Harvard has done interesting work on date-label legislation in the United States and the actual food-safety risks associated with those labels. Only a very small percentage of labels are there specifically to prevent someone from becoming ill. The majority are related to reasons other than food safety.

Katarina: Are there food items people should be more careful with?

Marc: Deli meats and fresh meat are examples where people should be careful. Beyond that, I think it is often about using your senses. Your body is quite good at judging whether something is fresh and safe to eat. I do not throw milk away simply because it is one day past the date on the carton. I smell it and make a judgement.

Katarina: What are the biggest pitfalls for consumers, and what are the easy fixes at home?

Marc: The simplest fixes are to plan meals and eat leftovers. On a Sunday, sit down and plan the week. In my family, we have what I call “Greatest Hits Friday”, where we eat the best leftovers from the week. We worked with a supermarket in the United Kingdom to understand food waste at home. We gave a panel of people technology to measure their waste temporarily, so we could understand why they were throwing food away. You might expect the main cause to be buying too much food—a carton of milk that was not used or yoghurt left at the back of the fridge. But most of the waste came from cooked food that was not eaten and leftovers. Once cooked food sits in a container for a while, it may seem less appealing and end up being thrown away. Plan your shopping and cook the right amount for the number of people. If you have leftovers, create a couple of rituals during the week to use them. I eat leftovers for lunch every day. The benefit is not only environmental; it is financial. Some people in our research were saving hundreds of pounds a year through small lifestyle changes. For some families, that was the difference between being able to take their children on a weekend trip and not being able to do so. Finally, trust your senses. Be sensible, but people often give themselves less credit than they deserve for judging whether food is still good to eat.

Katarina: You are also working with IKEA. Many people do not think of IKEA as a restaurant business, but it is one of the largest restaurant chains in the world. What does the work look like at that scale?

Marc: Winnow has helped IKEA reduce food waste by around 60% globally. A trip to IKEA often includes a visit to the restaurant for meatballs, plant balls, salmon or, in my children’s case, several orders of fries.
IKEA’s food business is a major part of the overall experience. Our work helps the business produce the right amount of food at the right time, particularly during peak periods when many customers are coming through the restaurants. The goal is to meet demand without leaving food in an oven for too long or ending the day with large quantities of leftovers. It is also about communication in the kitchen: are teams preparing the right amount of meatballs and fries, cooking the dishes they need and maintaining the right levels throughout the day? The work involves daily action in the kitchen, menu engineering at country level and procurement. What you measure, you manage. By providing a consistent metric, we can show where food waste can be reduced. The data also helps IKEA keep inventories accurate and make better buying decisions.

Katarina: IKEA operates across many markets. Do you see cultural differences when it comes to food waste?

Marc: Yes, and often for interesting reasons. In the United States, large portion sizes are seen as a sign of value, which can drive food waste. In parts of the Middle East, there is a strong desire to offer abundance to guests, meaning more food is presented than will be eaten. In Europe, there is generally strong mindfulness around food waste, and most organisations now have some kind of food waste strategy. Other markets are earlier in the adoption curve. Religious and cultural events can also create spikes in food waste. Examples include Christmas tables, Ramadan iftar meals, Thanksgiving feasts and other celebrations. These events are about gratitude, togetherness and humility, so it is counterintuitive that they can generate more waste. We have worked with clients to rethink those occasions and reduce waste while preserving the spirit of the event.

Katarina: What does the future look like when it comes to food waste?

Marc: I think change will accelerate, particularly as legislation in the EU moves forward. There is still a lot of room for innovation. I am especially interested in what innovation will happen in the home. There are businesses working on different parts of the supply chain, and apps could help people plan and shop more effectively. I also want to mention Olio, an organisation that helps people share surplus food. It has built a community of people who care about sharing food, reducing waste and helping one another.

At Winnow, we think AI will increasingly transform professional kitchens. Kitchens often collect very little data, and chefs rely heavily on intuition. Traditional technologies sit on desktop computers, but chefs do not want to stand in front of a desktop. They want tools that are with them in the kitchen and help them do their jobs. We are excited to help build that future.

Katarina: Marc, thank you so much for joining me. It has been great talking to you.

Marc: Thanks for having me.