Just ask IBF heavyweight belt-holder Anthony Joshua.
The 6-foot 6-inch, 234-pounder from Watford, England puts away nearly 3,600 calories daily -- almost double the 2,000-calorie FDA recommended intake for adults -- while in training.
His breakfast alone features five poached eggs over brown toast to accompany a bowl of porridge, a bowl of fruit, two cups of yogurt, and one cup of hot water, honey, lemon and ginger. He washes it all down with a liter of water.
Joshua's breakfast of champions consists of 1,095 calories, 42.8 grams of fat, 110.6 grams of carbohydrates and 54.7 grams of protein.
Lunch for the 26-year-old Olympic gold medalist includes two jacket potatoes with canned tuna and a plate of beetroot (a relatively modest 754 calories), while Joshua ends his day with a mound of chicken and rice plus sides of avocado and hummus (1,741 calories).
Joshua's biggest indulgence, however, would appear fairly innocuous to most: The traditionally British dessert of apple crumble, with a side of ice cream.
"I think you have to throw in a bit of guilty pleasure just to keep it sane," he admits, adding that he has the ability to get even larger -- though that would be detrimental to his performance in the ring.
"Yeah, (I can get bigger) mass-wise if I wanted to, easy. But, this is boxing, this isn't a bodybuilding competition, so I try to use my frame to be a good boxer, not to be as big as possible," he says.
Joshua -- who has a record of 17-0 with 17 knockouts -- acknowledges that his diet is large, but recoils at the idea of eating anything close to amount of food digested by his friend, former pro wrestler and now Hollywood action hero Dwayne "The Rock" Johnson.
"No, he's a beast," he laughs.
But even he can't compete with 22-time Olympic medalist Michael Phelps when it comes to the battle of the bite.
Phelps, who will compete in his fifth Olympics for the U.S. swim team in Rio next month, was ingesting up to 12,000 calories per day
during the 2008 Beijing Games. He says he has since toned down his diet considerably.
None of them, however, can lay a finger on competitive eating champion Joey Chestnut, who swallowed 70 hotdogs in 10 minutes
at the annual Nathan's Famous Hotdog Eating Contest on July 4.
Chestnut's intake consisted of 19,600 calories, 1,260 grams of fat, 54,600 milligrams of sodium and 700 grams of protein, according to ESPN's Darren Rovell.
Here's Joshua's daily training regimen intake broken down by meals:
Breakfast: One bowl of porridge (142 Cal, 3.2 g fat, 24 g carb, 4.4 g protein), one bowl of fruit (85 Cal, 0.5 g fat, 21 g carb, 1.1 g protein), two cups of yogurt (257 Cal, 9.1 g fat, 31.9 g carb, 11.5 g protein), five poached eggs (330 Cal, 25 g fat, 30 g protein), two pieces of brown toast (256 Cal, 5 g fat, 27.2 g carb, 7.7 g protein), one cup of hot water, honey, lemon and ginger (25 Cal, 6.5 g carb, 0 g protein) and one liter of water.
TOTAL: 1,095 Cal, 42.8 g fat, 110.6 g carb, 54.7 g protein
Lunch: Two jacket potatoes (322 Cal, 0.4 g fat, 74 g carb, 8.6 g protein), one can of tuna (314 Cal, 18.4 g fat, 1 g carb, 36.8 g protein) and two cups of beetroot (118 Cal, 0.4 g fat, 26 g carb, 4.4 g protein)
TOTAL: 754 Cal, 19.2 g fat, 101 g carb, 49.8 g protein
Dinner: One cup of white rice (227 Cal, 5.9 g fat, 37.8 g carb, 3.9 g protein), chicken thighs peri-peri platter -- preferably from fast food chain Nando's (592 Cal, 33.3 g fat, 1.1 g carb, 72.1 g protein, one half of an avocado (122 Cal, 12 g fat, 1 g carb, 1 g protein), and one plate of hummus (800 Cal, 1.9 g fat, 97.9 g carb, 23.3 g protein)
TOTAL: 1,741 Cal, 83.1 g fat, 137.8 g carb, 100.3 g protein
GRAND TOTAL PER DAY: 3,590 Cal, 145.1 g fat, 349.4 g carb, 204.8 g protein
And once all the calories are counted, who would be Joshua's ideal opponent? Someone considerably bigger than him: Eric Esch, a.k.a. "Butterbean," the 425-pound heavyweight with a 77-10-4 record.
"This game is hard enough as it is, so the easier the opponent, that's good with me," says Joshua.