CrossFit’s ‘No Sugar’ Rule Just Got Backed by Science

CrossFit’s famous “100 words of fitness” starts with food: “Eat meat and vegetables, nuts and seeds, some fruit, little starch and no sugar.” It’s short, blunt and decades ahead of what nutrition science is now showing us. That last part “no sugar” isn’t about being extreme. It’s about protecting metabolic health for life. And a really interesting piece of research in the last couple of years shows just how early that protection can start. crossfit.com

The big idea: the first 1,000 days matter

Researchers looked at people who were exposed to sugar rationing in the first 1,000 days of life, basically from conception through age 2. Because sugar was limited, these babies and toddlers didn’t get much added sugar. Decades later, those same people had significantly lower rates of type 2 diabetes (about 35% lower) and hypertension (about 20% lower), and the onset of those diseases was delayed by years. In other words, less sugar early on meant stronger health later. That’s wild. bmj.com

Why would that be? The first 1,000 days is a “programming” window. That’s when a child’s metabolism, taste preferences and even how their body handles carbs and blood sugar are being set. Flood that window with sweetened foods and drinks and you teach the body that high sugar is normal. Keep sugar low and you teach the body to run on real food.

This lines up with modern guidance

This isn’t just a quirky historical study. The World Health Organization says kids (and adults) should keep “free sugars” below 10% of daily calories, and even better below 5%. “Free sugars” is the stuff CrossFit is trying to get us to avoid. Sugar added to foods and drinks, plus sugary juices and syrups. The American Heart Association has already said kids under 2 shouldn’t have added sugar at all. So the CrossFit “no sugar” line is right in step with the best public health advice. World Health Organization

What this means for parents and grandparents

A lot of us in CrossFit have kids and grandkids around the gym. We meal prep, we track macros, we get our protein in, but the toddler’s sipping a flavored yogurt drink with 18g of sugar. This new research should make us pause.

Here’s the simple takeaway:

• Real food first: meat, veggies, nuts, seeds, fruit.
• Avoid added sugar entirely in the first two years whenever possible.
• Don’t train a sweet tooth early. Kids will like what they’re repeatedly fed.

That’s just CrossFit’s nutrition in family form.

“But fruit has sugar…”

Good question. The CrossFit line “no sugar” has always meant “no added sugar,” not “never eat a blueberry.” Fruit comes packaged with fiber, water, vitamins and satiety. The problem in the research wasn’t a toddler eating half a banana; it was easy access to refined sugar, sweet drinks and sweetened processed foods during a critical developmental window.

Why this matters to a CrossFit gym

CrossFit is in the chronic disease business, specifically, preventing it. We use constantly varied functional movements at high intensity to build capacity, but the front line is nutrition. If we can help families lower sugar exposure for the youngest members of the household, we’re not just getting Mom her first pull up, we’re pushing diabetes and high blood pressure farther down (or off) that child’s timeline. That’s exactly what the rationing study showed. science.org

And think about it from a community standpoint: if a gym normalizes “we don’t give babies and toddlers added sugar,” that’s powerful. It makes birthday snacks look different. It makes team parties look different. It teaches kids that savory, colorful, real food is normal.

What to do this week

1. Read labels on everything the under-2 crowd eats. If it has sugar, cane juice, syrup, honey, fruit concentrate added, find an alternative.
2. Swap drinks first. Water and milk beat juice boxes every time.
3. Model it. If kids see you drinking soda, they’ll want soda.
4. Tell caregivers. Share the “first 1,000 days” idea with babysitters, grandparents and daycare so they don’t undo your work.
5. Use CrossFit’s 100 words as the family rule. It’s short enough to remember and broad enough to protect health.

The bottom line? CrossFit’s “no sugar” wasn’t just about leaning out for better kipping pull ups. It fits perfectly with what researchers are now documenting: protecting kids from added sugar in the earliest days of life can protect them from chronic disease decades later. That’s the definition of scaling, taking a powerful principle and applying it to every stage of life.

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