Just in case anyone thought Nelson Peltz had lost his ardor for shaking things up at PepsiCo (PEP -0.50%), the activist investor lobbed a 37-page manifesto yesterday reiterating his case as to why the beverage giant needs to be broken up.

As is widely known, Peltz believes the company is working at cross-purposes and that having two distinct businesses would better unlock shareholder value that is being suppressed by the beverage division holding back the Frito-Lay snacks segment. The former is a declining asset, perennially playing second fiddle to Coca-Cola (KO -0.46%), while the latter is growing and has a long runway ahead.

Although Peltz also once argued that Pepsi should acquire snack maker Mondelez International, he gave up that campaign after being appointed to the Mondelez's board of directors.

The impetus for the investor's latest tilt at the windmill appears to be PepsiCo's rather lackluster earnings report last week, which Peltz described as "low quality" due to the "deteriorating trends" that led to the beverage maker offering weak guidance. The report underscores, he said, the urgent need to separate the two companies and unleash the entrepreneurial spirit that would allow each to thrive.

I tend to agree with the assessment and noted earlier this week that Pepsi's earnings report actually supports Peltz's case. It said snack volume grew 3% last year and that Pepsi expects the division would account for two-thirds of its revenue growth in the future. Snacks currently account for 52% of sales. Beverages, on the other hand, grew an anemic 1%, and operating profit in the Americas beverage division tumbled 10% as North American volumes dropped by mid-single-digit percentages. And as Coke's marketing deal earlier this month to collaborate with Green Mountain Coffee Roasters on a home-based DIY soda system shows, Pepsi continues to lag in innovation, too.

It's easy to imagine that an independent Pepsi beverage company would have made good on the rumors last year that it was interested in buying SodaStream International, the leading at-home soda maker. Instead, even if it makes that move now, Pepsi merely looks like it's once again playing catch-up to its rival's trendsetting ways.

When Pepsi announced its earnings, it also said that after giving due consideration to Peltz's proposal it ultimately rejected the idea because without beverages, its snacks become less relevant to consumers. I thought that overstated the case, and Peltz seems to agree, asking where the relevance is if Pepsi's beverage market share continues to dwindle and weighs on performance through lower margins.

Indeed, Pepsi continues to hold back the excellence Frito-Lay could achieve if it wasn't always having to prop up beverages. Even Dr Pepper Snapple Group, which has run into troubles lately with its new low-calorie diet soda offerings, has outperformed both Coke and Pepsi since its spinoff from Cadbury five years ago (a breakup led by Peltz). Dr Pepper last year beat Pepsi's earnings growth and expects to match it in 2014 -- all without the benefit of having a snack division to lean on.

No doubt Pepsi management will be equally dismissive of this latest salvo from the activist shareholder, but that was not his intended audience. Peltz said he intends to immediately begin meeting with shareholders -- even to hold public shareholder forums -- to allow investors to understand the benefits to be gained from splitting the company in two. It's clear Nelson Peltz has lost none of the fire that is burning for PepsiCo's salvation.