Flip over most protein bars and the pitch is flavour: chocolate, caramel, cookie dough. Flip over a RAW bar and the numbers that matter are 20g of protein and roughly 8g of fibre. That combination is the actual reason a RAW bar keeps you satisfied until your next meal, rather than wearing off within the hour.

Here's the research underpinning that.

Protein keeps your appetite hormones quiet

Feeling hungry isn't random — it's regulated by hormones, and the amount of protein you eat has a measurable effect on them. Researchers at the University of Texas Medical Branch ran a trial comparing diets with the same total calories but different macronutrient ratios. Volunteers eating a diet with 30% of calories from protein reported feeling fuller across the day than those on a high-fat diet, despite consuming the same energy overall. The researchers pointed to two likely drivers: protein takes more energy to digest than fat or carbs (raising diet-induced thermogenesis), and it prompts the gut to release hormones that signal fullness to the brain (Paddon-Jones et al., American Journal of Clinical Nutrition, 2008).

Every RAW bar is built to trigger that same response. The 20g of protein isn't only there for recovery and muscle — it's doing active work on your appetite for hours afterwards.

Fibre works a second angle

Fibre doesn't rely on hormones the same way — it changes how quickly your stomach empties. A 2018 review in the European Journal of Clinical Nutrition pooled results from short-term feeding trials and concluded that higher fibre intake consistently slows gastric emptying, meaning food sits in the stomach for longer and fullness lasts longer as a result (Warrilow et al., European Journal of Clinical Nutrition, 2018). A broader review of the evidence on fibre and weight, spanning both population studies and controlled trials, came to a matching conclusion: people who eat more fibre tend to eat less overall and carry less body fat (Slavin, Nutrition, 2005).

Put the two together and you get appetite suppression from two independent directions at once — protein acting on hormones, fibre acting on digestion speed. That's a harder combination to out-eat than either nutrient working alone.

The point of building a bar this way

Most bars on shelf are formulated to taste like dessert, because that sells on impulse. RAW took the opposite starting point: a functional flapjack, formulated around protein and fibre content first, taste second. It's currently the UK's #2 best-selling protein bar on Amazon — and the people buying it repeatedly aren't doing so for the sweetness. They're buying it because it does a specific job: it stops them getting hungry again too soon.

That's the whole idea behind "staying full" as a category, rather than another treat to snack on.

A word on getting started

If your current diet is fairly low in fibre, don't go from almost none to several bars a day overnight. Mayo Clinic recommends raising fibre intake in small steps — around 3g extra per week — alongside plenty of water, because a sharp increase can cause temporary bloating or discomfort while your gut adjusts. Ease into it over a couple of weeks and your system catches up without any issues.

Sources

Paddon-Jones, D., et al. (2008). Protein, weight management, and satiety. American Journal of Clinical Nutrition, 87(5), 1558S–1561S. Link

Warrilow, A., Mellor, D., McKune, A., & Pumpa, K. (2018). Dietary fat, fibre, satiation, and satiety—a systematic review of acute studies. European Journal of Clinical Nutrition. Link

Slavin, J. L. (2005). Dietary fiber and body weight. Nutrition, 21(3), 411–418. Link

Mayo Clinic. Dietary fiber: Essential for a healthy diet. Link