Walking into the 600,000-square-foot Optimum Nutrition plant in Downers Grove, Illinois, is an intense sensory experience to say the least.

The sheer scale of the facility brings to mind the last scene from "Raiders of the Lost Ark," where the Ark of the Covenant is wrapped and placed among other shrink-wrapped specimens. But with the matching white lab coats, orange helmets, and pervasive aroma of cocoa powder, I also felt like I had pulled back the curtain at Willy Wonka's Chocolate Factory. When we walked into a smooth-walled blending room crawling with busy employees pouring ingredients into an industrial-sized funnel to the mixing vessel below, I half-expected to find Augustus Gloop himself wedged halfway down the tube.

All pop-culture nostalgia aside, though, the immediate—and lasting—impression of visiting one of the largest sports nutrition manufacturing facilities in North America is just how complex and exacting of an operation it is to make the supplements that many of us now take for granted. In an industry that has a reputation for being sometimes less than rigorous, this was undoubtedly serious business.

For a few days, I was fortunate to be among a group of fitness insiders invited behind the scenes to see how Bodybuilding.com's longtime best-selling brand operates. If you've ever had a scoop of Optimum Gold Standard Whey, AmiNO Energy, or any of their other products that are household names in the weight room, here's the story behind them!

Consistency: The New Quality

When the sports nutrition industry first started gaining momentum, what set good companies and products apart from their not-so-good counterparts wasn't simply taste, or price, or even marketing. More than anything, it was consistency. With a community as tightknit as bodybuilders at the time, if a customer were to unscrew a lid to find clumpy powder or a dramatic change from their last purchase, word would spread quickly around gyms. Today, it spreads more quickly than ever in the form of scathing or raving online reviews.

This is precisely why Optimum Nutrition's manufacturing facility has approximately two dozen checkpoints for quality control and consistency. Just when you think you've seen the last person scoping or testing a bottle of whey or pre-workout, here comes another. From testing every raw ingredient when it first enters the facility to X-raying the capped bottles on the final production line to make sure the scoop is at the top—yes, they know you hate fishing for that plastic scoop—this company does everything in its power to make sure each and every bottle is exactly as the customer expects it to be.

"The word 'quality,' has started to lose its currency in recent years," says Mark Gutsch, Director of Manufacturing Operations and our guide on this tour.

It's not that quality isn't important—of course it is, and Gutsch says that in the search for ever-higher quality, Optimum Nutrition rejects more raw protein each year than its closest competitor sells. But he rightly points out that everyone claims to have "the best quality product" or "the highest quality ingredients." The new emphasis? Consistency.

Here's why: More than ever, consumers realize that one protein shake—no matter how high-quality or delicious—isn't going to get them to their goals. The same goes for one meal, one workout—one anything. It's only after months of nailing your meals, workouts, and supps that it all comes together, you look in the mirror, and realize you've seriously changed.

Customers need to know what they're getting, not just in one jug of whey, but in every jug. Loyalty, not just single purchases, are what drives the company. And by focusing on consistency, Gutsch says, Optimum Nutrition ensures that when you purchase a bottle of Optimum Nutrition Gold Standard Whey, you know exactly what you're getting over and over again.

Changing with the Times

The origin story of Optimum Nutrition is familiar to anyone who ever opened up a supplement container, felt disappointed, and wondered if they could do better. Fed up with a lack of consistency—and yes, quality—in sports nutrition in the mid-'80s, the athletic brothers Mike and Tony Costello decided to do something about it: start their own company.

With word-of-mouth powering them along the way, the fledgling Costello's Health Distributors grew quickly and evolved into a global powerhouse. Today, it encompasses not only the most recognizable brand of protein on the planet, Optimum Nutrition Gold Standard, but also multiple recognizable brands under one roof. 

They have also branched out from strictly bodybuilding supplements and now boast an immense array of products tailored to meet the needs of every type of athlete or health-seeking consumer.

"Our consumers aren't just looking for a good quality protein powder any more, and they are not spending all their time lifting weights in the gym," explains Sarah Teeter, Brand Director at Optimum Nutrition.

She points out that over the past few years, lifting weights has become no longer just an end itself, but a means to support other activities and goals in their customers' lives. Sure, there's a timeless appeal to building bigger muscles and shedding body fat, but gym-goers today are doing more than ever before, and taking more supplements to help them do it.

"It's no longer just about 'build muscle,' says Teeter. "It's about recovery, repair, and rebuild."

Beyond the Shaker

Just as the definition of fitness has changed, protein powder is no longer relegated to the shaker cup. It's popping up in lattes, cookies, breads, and yes, even donuts.

As Teeter explains, "The average consumer has gotten wise to what the fitness industry has known for decades: We could all use more protein."

Much of Optimum's recent product expansion has been in creating new, easy ways to get that protein. On the top floor of a glittering glass building overlooking the treetops of the neighboring nature preserve, our hosts at ON laid out a buffet of their latest ready-to-eat products and on-the-go fitness supplements, each designed to make the transition from gym to life easier.

A few include protein cake bites, protein wafers, protein almonds, and even whey-isolate-infused protein water—seriously! There are also their unbelievably delicious, delicately flavored Protein Nature Bites, or at least, there were until I attempted to smuggle the entire inventory home in my carry-on luggage (sorry, not sorry).

All of these products are designed with the idea that health and fitness doesn't have to be just in the gym, and protein doesn't just have to come from a shaker.

"We set strict macronutrient guidelines and calorie totals for our products with the goal of using the best possible ingredients," explains Andrew Lynch, VP of Research and Development. "We keep testing and developing until we have a final product that fits those standards but still tastes great—we never want to sacrifice taste."

Each of these new products comes with its own unique challenges in terms of nutrition, texture, and shelf life. Those challenges are the domain of staff members like Matt Wengerhoff, a food and innovation technologist in Optimum's basement R&D lab.

"We use a variety of methods to develop the best possible texture, mixability, and flavor for each of our products," said Wengerhoff during a tour of the lab. "We test and retest each product to ensure it can hold up in any conditions with no loss of integrity, efficacy, or flavor."

Ever left your pre-workout in your car in July? Had a package delivered while you were out of town and had to cross your fingers and hope that the humidity wouldn't ruin it? Wengerhoff's team is in charge of making sure your product stays consistent and effective no matter what. They still haven't gotten a scoop that will magically float forever on top of the protein powder, but I'm told they're working on it.

Proven to be Number One

ON recognizes the fitness industry is always changing, but it's never been content to be subject to the whims of the industry. As an industry leader, ON has always striven to innovate first, and set positive trends in supplement testing and manufacturing from the top down.

And yet, lurking in the background of all of this innovation like a proud parent, are the tried-and-true products longtime lifters know and love: Gold Standard Whey, AmiNO Energy, Gold Standard Casein, and Serious Mass, among others. These are the first products that many athletes try, and for many of us, they remain our favorites. Case in point: Optimum Gold Standard Whey was the top-selling product on the Bodybuilding.com website when I first started working here nearly a decade ago—and it still is today.

Want to know why people like it? You'll find over 9,000 reviews on Bodybuilding.com alone telling you the details, and thousands more for each of those other flagship products. No other brand can claim the same level of long-term commitment from its users, which is why ON recently launched a new marketing campaign built around a single word: "proven."

The executives I spoke with said their word choice was all about cutting through the din of the noisy supplement marketplace. "Proven" is not about convincing you to give then a one-time shot, or shouting the same message as everyone else. It's about reminding customers of the quality and consistency that propelled this company to the top of the industry and has kept them there for decades.