Eating huge quantities of food is an unobtainable fantasy for some and an everyday luxury for others. To Adam Richman, voracious host of Man V Food (Mon, 9pm, Good Food), it's a career choice.

Man V Food is obscene on many levels, but daft on several more. The format couldn't be much simpler: every week, Richman travels to a city (Memphis this time) and samples its most notorious "pig out joints": the sort of quintessentially American restaurants where everything is charbroiled or smoked or sizzled to death in a deep fat fryer vat the size of a swimming pool; places where each mammoth portion comes with a side order of type two diabetes. Establishments of this kind often tend to have a "challenge" item on the menu – a dish so offensively huge, anyone who successfully manages to eat it has their portrait hung on the wall. The end of each episode sees Richman taking on one of these challenges, hence the title. That's all there is to it.

Essentially this is Top Gear for food: a jokey, blokey exercise in excessive indulgence. It's all sensation, sensation, sensation. Just as Clarkson emits orgasmic whimpers when his driver's seat judders on acceleration, so Richman groans like a man having his perineum tongued by three cheerleaders as he ingests each warm mouthful of stodge. If food is the new porn, this is an all-out orgy between wobbling gutsos and farmyard animals – a snuff orgy, no less, since the latter end up sawn in half and smothered in BBQ sauce.

Plenty of cattle get eaten; at times Richman may as well lie down, open his gob and let a herd stampede directly into his stomach. Entire carcasses are greedily consumed by overweight folk with juice dribbling down their chins, tearing flesh from charred bones with their glistening teeth. It's like sitting in Sawney Bean's cave. Meat and skeletons, meat and skeletons. A sequence in which Richman peers inside an oven at Memphis's premier rib joint to witness a landscape of scorched and smouldering ribcages almost resembles the aftermath of the Dresden firebombing. This is definitely not a programme for vegetarians.

Things reach an insane peak (or more accurately, trough), as Richman takes on the eating challenge. This week he faces the 7 ½ pound "Sasquatch Burger" at the Big Foot Lodge. 1,300 people have attempted to eat one; only four have succeeded. This high failure rate is hardly surprising when you see the bloody thing: it's the size of a sofa cushion. The bun alone accounts for two pounds. The burger itself is an ominous cake of mashed cow as thick as your thigh. When he first tucks in, Richman is chirpy and cocky, shovelling handfuls of meat down his neck with the gluttonous abandon of a self-aware Homer Simpson. Several minutes later, as it becomes clear he still has an immense mountain of food to get through, he appears sickened and woozy – presumably because his blood sugar levels have hit a dangerously narcotic high as his stomach desperately tries to break down the busload of beef that's just appeared inside it. This is the point at which the show stops being fun. It's like watching a man dealing with an instant, unexpected pregnancy.

But what I'd really like to see is what happens the next morning, when the show presumably turns into Man V Poo, as Richman empties the dauntingly substantial, hopelessly compacted contents of his engorged colon, clenching the bathroom doorhandle between his teeth as he attempts to give birth to a leg-sized hunk of fecal sod without killing himself. Cue footage of him sweating, shaking and sobbing like a man impaled on a clay tree, before eventually squeezing out a log with the dimensions and weight of a dead gazelle in a greased sleeping bag. As he mops his brow (and backside), he smiles weakly with exhausted triumph, whispers farewell, and the credits roll. And we've all learned something about the price of excess.