This carbohydrate is Anthony Joshua's power-packed secret weapon
Anthony Joshua is an absolute machine.
The IBF world heavyweight champion trains three times a day, 365 days a year... and it shows.
The 27-year-old is the ultimate physical specimen - he's 6ft 6in tall, athletic and ripped to death.
While the old saying goes 'physiques don't win fights', Joshua would disagree.
His incredible conditioning is what's behind the blistering strength, power and athleticism he possesses, which has seen him knock out all 17 of his opponents on the way to the heavyweight world title.
Here we took an in-depth look at the training that has forged him into the most feared fighter in the heavyweight division.
But underpinning his gruelling strength and conditioning programme is a strict nutrition plan.
Food is fuel and Joshua's diet is designed for maximum performance and optimal recovery both in the gym and in the ring.
The Olympic gold medallist goes through 4,500 calories a day of nutrient-dense food and fuels his intense gym sessions with good carbohydrates.
While he consumes rice, noodles and fibre-rich green vegetables, one of the carbohydrate sources he swears by is the humble yam.
He explained that pounded yam, a Nigerian staple, is one of his key training foods leading up to fights.
"It just keeps you strong," he told Sky Sports before the Dominic Breazeale fight. "It's a dense form of mash potato. If you eat that enough and you train then it's a big carb load."
If you've not encountered yams before, they're similar to sweet potatoes - but they grow in Asia and Africa, although you can probably now get them down at your local supermarket.
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The reason they're such a useful and power-packed source of fuel for fighters, or anyone else who trains and wants to get lean, is that they're a complex carbohydrate.
This means they're slow burning so you get a constant and steady supply of energy throughout the day, rather than the energy spike and then crash you get with 'simple' carbs like white bread.
Yams are high in fibre, which slows digestion, keeps you fuller for longer and keeps your digestive system clean and healthy so you an more efficiently absorb nutrients from your food.
They're full of low GI (glycemic index) carbs. This means your blood sugar is kept stable and you don't get that energy crash an hour after you've eaten - or those nasty sugar cravings.
Yams are also full of Vitamin C and Vitamin B6, according to LiveStrong. Vitamin C helps with tissue repair and it has antioxidant properties that protect against the effects of free radicals after exercise which can include muscle breakdown, cell damage and ageing.
Vitamin B6 assists in protein metabolism and synthesis of red blood cells, which fellow B Vitamin Thiamin helps turn carbs into energy.
All this makes yams a powerful nut great if you're training for a heavyweight world title but also equally good if you're looking to lose weight and get lean.