In a filing, Loeb's Third Point also reiterated that a full board turnover is necessary for the soup company to find its direction.
Third Point said Campbell could fetch a takeover value of $52 to $58 per share, a 58 percent premium on the soup company, based on its morning trading price of $36.52 a share.
Campbell shares were down 1.5 percent Monday afternoon.
The proxy statement filed with the SEC comes months after Third Point revealed 5.65 percent stake in Campbell. In September, it announced its intention to campaign to replace the entire Campbell board, unhappy with the results a of Campbell's three-month critical review. The review was sparked by Campbell's disappointing earnings and surprise departure of its CEO. While Loeb has pushed for Campbell to sell itself as part of the review, Campbell announced in Augustit is selling its international and fresh food businesses.
In response to Third Point's filing, Campbell said the board "remains committed to evaluating all strategic options to enhance value in the future."
Meantime, the company has acknowledged a number of its missteps. It chased too many initiatives at once and had scant reason to get into fresh food, where it had little experience and no reputation. It also more than tripled Campbell's debt load through its $6.1 billion acquisition of pretzel maker Snyder's-Lance, looking for growth to counter slowing soup sales.
Campbell has returned 19 percent to shareholders over the past 20 years, compared with 306 percent by the S&P 500, the Monday presentation stated. Kellogg has returned 261 percent, General Mills has returned 331 percent and Hershey has returned 359 percent, it added.
Its plan to sell certain business were insufficient to Loeb.
"Given challenges, Campbell conducted a strategic review, but then failed to take bold action to remedy the situation and largely recommitted to the failing status quo," Third Point said in its presentation.
Loeb said he calculated a likely value for Campbell by looking at previous deals in the food industry, like Conagra Brands' acquisition of Pinnacle Foods this year. The food industry has consolidated in the past few years, as slow-growing food conglomerates have combined to cut costs where they cannot grow the top line.
While Campbell has long been considered a takeover target, its most likely buyer, Kraft Heinz, has struggled with growth in recent years. The latter's stock has fallen more than 28 percent since January. Should Kraft Heinz be interested in buying the soup company, there is uncertainty among analysts it would be willing to pay a big price.
Warren Buffett, a large stakeholder in Kraft Heinz, recently told CNBC it's "very hard" to offer a premium for a packaged food company due to the challenges in the industry, like rapidly changing consumer tastes.
Meantime, Third Point faces obstacles in its campaign, with descendants of Campbell's founder owning significant stake in the company. Two of them, Bennett Dorrance and Mary Alice Dorrance Malone, together hold 33 percent of Campbell and have resisted past pressure to sell the company. A separate set of family members own a combined 7.9 percent stake through the Campbell Voting Trust.
To fortify his campaign, Loeb has linked up with another descendant of the founder, George Strawbridge Jr., who has a 2.8 percent stake.
"[The] incumbent board, which created the current situation, can no longer be relied upon to lead the company, and shareholders deserve a new path forward," Loeb's presentation said.
Loeb also chastised Campbell for a CEO search that not yet reached a conclusion months after announcing Morrison's departure.
Campbell has not yet chosen a date for its annual shareholder meeting, according to Third Point.