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IMPACT Math – How We Arrived at These Numbers

May 18, 2019
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IMPACT Math – How Did We Arrive at These Numbers?

Just about every food waste advocate, scientist, and knowledgeable chef says something along the lines of “To reduce food waste at home, you should meal plan and grocery shop from a list.”

We agree. That is central to what we do at Ends+Stems. We give home cooks simple but powerful tools that will make a dent in the overwhelming quantities of total food wasted in the U.S.A and across the globe.

But, more food is wasted in our homes than any other single place and no one has ever measured the impact of that advice.

How much food did you not waste this week because you followed a meal plan and went grocery shopping from a pre-written list (which you ideally checked against the ingredients you had in stock at home)? The honest answer is that we don’t know. There has NEVER been a comprehensive study to measure it.

The first piece of our solution was building the web-app. As a long time chef working in people’s homes, Alison knew that families are pulled in so many directions that few have time to sit down and meal plan. (A study we ran with 1000 moms found that fewer than 6% of them meal plan even once per month). For 9 months, Ends+Stems operated in beta mode – we sent meal plans and grocery lists to people, but no website was involved. We asked our beta testers to pay attention to their waste and habits. Our anecdotal results confirm that people “feel” like they wasted less food with Ends+Stems and getting our weekly menu made them “think about food waste more often” inside and outside of their homes.

On one hand, it’s a huge success to have a new group of people thinking about their food waste. Its ok to be emotional and anecdotal, that’s how people connect and culture begins to shift. On the other hand, we have a real climate crisis looming and feeling good is not going to save us. We need cold, hard, measurable, repeatable facts. Ends+Stems is here to lead the way.

If you want to be part of our study to MEASURE CONSUMER FOOD WASTE IMPROVEMENTS BY MEAL PLANNING, please drop us an email today – hello@endsandstems.com with the subject “Measurement Study.”

In the meantime, we really wanted to give you some validation for your efforts and help inspire you to stay active in the Ends+Stems community. We’ve put together two different “Pizza Math” equations to make reduced carbon emissions tangible. Here’s what we did:

What’s In My Fridge? Recipe Search

The math is based on:

  1. Most people each 3-5.5 pounds of food per day but feel full around 4 pounds
  2. We used 4 pounds per person per day
  3. Assuming 1 pound is wasted at dinner time, per person
  4. Our recipes are mostly for dinner, so we’re assuming you’re eating dinner
  5. We assuming you searched for this recipe because you had these ingredients going bad and would have thrown them out soon
  6. We assume everyone licked the plate clean (no leftovers created)
  7. 1 pound of food (aka 2.2 kg) equals 4.18 CO2-E (kg) – aka carbon emissions or “greenhouse gasses”
  8. Average slice of pizza weighs 4oz so 4 slices equal 1 pound

(Co2-e  – is one of the standard notations for a carbon equivalent)

Therefore, for every serving of dinner cooked from this recipe, you are NOT wasting 4.18kg carbon emissions, and that equals 4 slices of pizza.

1 serving on the recipe = 1 pound of food saved = 16 ounces food saved = 4.18 CO2-E (kg) = 4 slices of pizza

This is what we show you when you do a What’s In My Fridge? Recipe Search and hit the “I Cooked This Button.”

Meal Plan Subscriber’s Impact

This math is different because we send you to the store to purchase food. We do encourage you to check the grocery list against your food in stock before you make new purchases, but unlike the What’s In My Fridge? search, the majority of perishables you’re buying have an intended use.

This math is based on:

  1. Subscribers set their number of servings needed per recipe
  2. Since you can change this, we assume your default is accurate for your household most of the time
  3. Best results in food waste reduction come from cooking all three meals each week, because that’s how we design the recipes
  4. We assume you’re serving the default portions and cooking all 3 recipes weekly
  5. The average person wastes about 1 pound of food weekly (which equals 112 ounces), about ⅔ of it is edible. We’ll call this 74 ounces weekly of edible food wasted.
  6. Divided evenly among 3 meals per day, that’s about 3.5 ounces per meal time. But our (admittedly small) study suggests a much higher percentage is wasted in dinner preparation than lunch or breakfast because of the variety of meals prepared and number of ingredients used.
  7. So, instead of dividing it evenly, we estimate that 6 ounces per serving of each recipe cooked while meal planning is food that is not wasted (that might otherwise be without meal planning).
  8. Which is then multiplied times 3 recipes per week for a total of 18 ounces per serving cooked. 18oz = 1.2 pounds
  9. That converts to .36 CO2-e (kg) per person per week. And 4.5 slices of pizza (4 ounces each).
  10. In our subscribers profile we then show the full potential in pounds of food not wasted, converted to number of 4 ounces pizza slices, and kg of carbon emissions.

Our “Community Numbers” combine the total from all of our Meal Plan Subscribers AND What’s In My Fridge Recipe Search users and we keep counting up!

The Problems With Our Math

Please, let us be the first to poke a thousand holes in this math. There are myriad assumptions here that we know aren’t proven and what’s more, we couldn’t possibly calculate them. If you didn’t search What’s In My Fridge? to cook that chicken, it’s impossible to know whether you would have cooked it tomorrow.

However, once people know their food waste is being measured, they waste less! This is great news as our community knows, just by using our site, our recipes, reading our tips of the week, and checking out our feed on instagram, Ends+Stems users think about food waste more often and therefore waste less.

Want to discuss further? We’d love to! Want to fund our study? We’re looking for a grant. Email hello@endsandstems.com or take it to our facebook group where this would be a great conversation.

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