Shaich took the challenge to find out what it's like to live on food stamps. He's blogging about the experience on LinkedIn.
The average person on food stamps receives $4.50 per day in assistance, according to The New York Times.
When Shaich went shopping with his weekly budget of $31, he was surprised that he couldn't afford coffee, fruit, yogurt, or milk.
Shaich ended up settling on a daily breakfast of cereal without milk, a lunch of lentils and chickpeas, and a pasta dinner. He bought carrots to snack on in between meals.
By the third day of the challenge, Shaich wrote that his diet left him feeling "bloated and weak."
On the fourth day, Shaich said his thoughts were "consumed by food."
"When is my next meal? How much food is left in my cabinet? Will it get me through the week? What should I spend my remaining few dollars on? What would I eat if I had no budget at all?" Shaich wrote.
He also noticed a strain on his relationship with his wife, Nancy:
"I snapped at her for over-portioning my spaghetti. I felt so much anxiety about the possibility of running out of pasta that I completely overlooked my wife's good intentions in helping to prepare my dinner. I have to imagine that this is a common source of conflict in households marked by food insecurity."
He'll continue blogging for the next three days.
The challenge isn't Shaich's first attempt to raise
He spearheads Panera Cares, a collection of cafes that offer free food and operate on donations.