Countless fast-food chain concepts have exited the market in the last fifteen years. It's a brutally competitive industry, after all, characterized by low profit margins and constantly shifting consumer tastes. Even successful burger, pizza, chicken, or Tex-Mex brands tend to produce only modest sales and profit growth amid the constant market share battle.

Investor fortunes can be made in this mature sector, though, even in a short time frame of less than 20 years. An investor who split a $10,000 portfolio equally between Chipotle Mexican Grill (NYSE:CMG) and Domino's (NYSE:DPZ) would have made about 16 times their original allocation by holding those stocks from mid-2006 to mid-2020. A similar investment in the S&P 500 would have yielded just a 150% increase.

Five young adults sharing a delivered pizza.

Image source: Getty Images.

Two winning approaches

What stands out about these two companies is that, although they weren't the first to introduce consumers to their respective flavor niches, they used innovative approaches to steadily win market share.

For Chipotle, that meant bringing restaurant-quality preparation techniques and ingredients to the fast-food space. The burrito specialist also pioneered an assembly line production model that helped it serve hundreds of meals per hour during peak lunchtime service. These simple but effective advantages allowed Chipotle to boost annual sales to $5.6 billion in 2019 -- up from $820 million when it went public in 2006.

Domino's growth story relies even more on its selling approach. It produces a simple food that's made by countless other restaurant chains, both large and small. But the company relied on a small, efficient store footprint to help it generate cash and provide consistent value to customers.

The fast-food specialist counts technology as a core competitive advantage, too. Recent innovations include its "hotspot" program that added thousands of non-traditional delivery venues (i.e., parks and beaches) to its footprint. Thanks to assets like these, Domino's grip on the massive pizza delivery industry has grown to 29% in 2019 from 18% a decade earlier.

Overcoming challenges

It wasn't an easy ride for shareholders, who were tempted with many seemingly good reasons to sell these stocks over the last few years. Domino's reported a painful growth slowdown in fiscal 2019 as restaurants and third-party aggregators flooded into the home delivery niche. It has also struggled with sluggish demand in many international markets since early 2018.

Chipotle has tested investors' patience even more by seeing its stock price collapse following its food safety challenges. These concerns threatened the wider business and led to a dramatic shake-up in the management team and the chain's sourcing and supply chains.

But both chains have put these issues behind them as they post rebounding sales trends.

Catching lightning in a bottle

Of course, no one had the benefit of hindsight when considering buying these stocks back in 2006, and this portfolio exercise is admittedly biased by cherry-picking standout winners. Two of the industry's biggest players, McDonald's and Starbucks, posted more modest, but still market-trouncing gains of 480% and 318%, respectively.

Still, the fantastic growth that Chipotle and Domino's have posted since 2006 demonstrates that investors don't have to bet on tiny, obscure stocks or unproven business models in areas like biotechnology and cryptocurrencies to achieve life-changing returns. Often, the stock that turns a good retirement portfolio into a great one is a business engaged in something as simple as feeding hungry people a consistently high-quality meal on the go.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.