British funnyman Timothy Spall, of Harry Potter fame, dropped jaws at the Venice Film Festival with his magical weight loss. But not before his actor son Rafe Spall (BFG, I Give it a Year) dropped an equally dramatic six stone. That makes Rafe roughly 80 pounds thinner for yanks doing the math! So weight loss is apparently a family tradition, but so say the Spalls, is weight gain. Both actors shared their secrets on how and why they effected such transformations.

Obesity runs in the family

Rafe Spall says he was always overweight through his twenties.

And, like his dad, he was always cast as the funny fat boy. Timothy Spall recently portrayed one of his most serious roles as Irish labor activist Ian Paisley in The Journey. But prior to that, it was mostly silly, buffoonish parts like Wormtail/Peter Pettigrew in Harry Potter. That's what people, including son Rafe, love about Spall - his sense of comedy. But being typecast as the jolly joker loses its charm. Rafe Spall wanted to be taken seriously and cast as the handsome leading man, instead of the chubby sidekick, so he cleaned up his act and his plate. Now the sexy Spall is being hailed as the next Hugh Grant! And like son, like father--in 2014, Spall, Sr., got serious about losing his weight and fat man image.

Looking good is feeling good

Rafe Spall says obesity is no laughing matter--it's painful, humiliating and discouraging. The more you gain, the less you care and the more you eat, he explained. It wasn't a matter of self-confidence. Even at his fattest (18.5 stone or 260 pounds) Spall had the cojones to do nude scenes. It was more a matter of willpower.

When he found that, it gave him the boost to get busy and shed the weight. For Sir Timothy Spall (he's an OBE, yanno), weight loss was a matter of trumping the food addiction and a desire to avoid health problems. Diabetes, hypertension, high cholesterol, heart trouble, sexual problems, erectile dysfunction (to name a few issues) dog the obese person.

But Spall has a major struggle. He says he is a glutton and lacks the wiring to know when he's satiated. Spall has to basically con himself into feeling full even though his hunger meter is broken. That experience is shared by many people who have gained a great deal of weight and then lost it. There is a constant battle between hunger pangs and cravings and a desire to be healthy.