In London, en route to Britain’s oldest wine merchant, Berry Bros. & Rudd, you might pass the Ritz, an oyster bar with ice piled invitingly in the window, a pâtisserie and several Michelin-starred restaurants. The gastronomic temptations are so compounded that were the Romantic poet Lord Byron alive today, he would probably break into a sweat and stagger on, eyes blinking, tunnel vision setting in.

Byron, who teased his mother mercilessly for being so fat she couldn’t catch him to discipline him, grew up to be an obsessive dieter, with a predilection for exercise deemed “violent” by one biographer. He’s said to have lived for periods on dry biscuits and white wine alone, and exercised in lots of clothing to make himself sweat more.

He first visited Berry Bros. when he was 17, at the beginning of 1806. The tea, coffee and spice emporium established in 1698 had by then moved into selling Champagne, port, and wines from Bordeaux, but had kept its giant coffee scales, adding a seat so customers could be weighed. (The scales still sit in the entrance way of the little-changed shop at No. 3, St James St.)

Personally, if I were visiting a fancy shop to give myself over to premium wines, I could happily forgo being reminded of my weight. But because scales were relatively rare into the 19th century, “to know your weight was a sign of well being,” explains Berry Bros. shop manager Francis Huicq.

By the time of the Beau Monde, Berry Bros appeared to be something of a drop-in center for dandyish scenesters such as Beau Brummell, a fastidious groomer who weighed himself more than 40 times and probably took pleasure in the results – he lost 26 pounds (12kg) over a seven-year period. Just as well: while still bulky, he was publicly snubbed by the Prince Regent at a ball. Brummell responded by turning to the Prince’s companion and asking, “Alvanley, who’s your fat friend?”

For a young Lord Byron, though, knowing his weight may have been agonizing. At 17, he already weighed 13st 12lb (88kg). By 19, in the summer of 1807, he was down to 10st 13lb (69.4kg); two weeks later he was 11st (69.8kg), and another few weeks after that, he was 10st 11lb (68.5kg). “He was bulimic,” Huicq speculates, “and sometimes he didn’t restrain himself and he was basically purging himself. So he was yoyo-ing all the time.”

The Prince Regent’s famously sizable weight doesn’t appear to have been recorded at Berry Bros., but in 1898, the shop’s ledgers noted that the Duke of Clarence, Prince Albert Victor (Queen Victoria’s grandson, and the royal briefly suspected of being Jack the Ripper), weighed 11st 9lb (74kg) in a “light overcoat.” The Marquess of Granby (around 12 to 13 stone/76-82kg) weighed himself almost every week for the whole four years he was Lord of the Bedchamber to Prince Albert, the Queen’s husband. Perhaps Albert teased him about his weight, or perhaps Granby had too much opportunity to view himself in well-cleaned mirrors.

Female weights were kept in a separate ledger, and a history of Berry Bros. records that a certain shop attendant named Strange (“tall, reticent and unmarried”) was particularly fond of weighing the ladies. “With what unction did Strange bring out the special volume reserved for the fair sex!” the book records. “With what fussy discretion did he make the lady comfortable in her seat on the scales! With what delicacy did he add weight to weight as though he were weighing a fairy!”

These days, it’s rare that a customer is formally weighed. Movie star Matt Damon once was – he had hired the dining room, chef and waiting staff at Berry Bros. for a wedding anniversary dinner. Huicq is relatively tight-lipped about the occasion: “I don’t know where is the ledger for Matt Damon,” he says, “but sometimes men would be weighed with their Wellington boots, their hats... So, to continue the tradition, it is mentioned in the ledger that he had a wallet in his hand.”

The discovery of Byron’s oscillating weight has led several historians to reinterpret the meaning of “Byronic” looks and to intimate that the poet was a pathetic fatty. “There are lots of images where he looks like a pallid, slightly podgy young man,” one historian said snarkily to The Observer. “Just not impressive.” Byron has since been headlined a “celebrity diet icon” and credited with inventing “the celebrity weight-loss craze.”

As to what Byron may have purchased at Berry Bros. when he tore himself away from the scales, Huicq can only take a punt, for records no longer exist. “I would imagine some clarets, and ports – especially in times of war with France when French imports were banned in the United Kingdom.”

It’s a distressing thought that if the poet – once famously described by Lady Caroline Lamb, with whom he had a messy affair, as “mad, bad and dangerous to know” – was around today, he might have been susceptible to the marketers of low-calorie wines.