Louis XIV's entire family was apparently a bit chunky, but his younger sister got a nickname:
What he lacked in confidence, the Dauphin certainly did not make up for in physical attraction. He was heavily built, his weight increasing further as time passed. There was some kind of gene of fatness in this branch of the Bourbon family, which may have been glandular in origin. His father had been enormously fat. Maria Josepha's father Augustus III had also been obese, while the prodigious physique of her grandfather Augustus II had been saluted with the cognomen "The Strong"; at least one of her brothers, Clement, was extremely fat. Wherever the inheritance came from--possibly from the meeting of two similar genes--there was no doubt that Louis Auguste, his nearest brother the Comte de Provence and his younger sister Clothilde all had what would now be called a weight problem. Clothilde was actually nicknamed "Gros-Madame." They also all had enormous appetites.
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Poor plump Clothilde, the Gros-Madame of unkind court nomenclature, was nine, as "round as a bell" with her circumference thought to exceed her height.
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The marriage celebrations for the King's sister, Gros-Madame Clothilde, which followed in the second half of August, were also no great comfort to the Austrian Archduchess [Marie Antoinette]. The bridegroom was the Prince of Piedmont, heir to the Kingdom of Sardinia, which made the third Savoyard marriage in a row within the royal family, to say nothing of a half-Savoyard heir to the throne, the infant Duc d'Angouleme. Poor Clothilde's notorious weight cause the wits to say that two Savoyard princesses had been received in exchange for one very heavy French one. That weight had indeed caused some concern to the grandfather of the bridegroom, King Charles Emmanuel III, on the grounds that if the fourteen-year-old Clothilde was fat already, she would certainly get fatter still in Savoy, as French women always enlarged on Italian food; his anxiety focused on the question of heirs. Clothilde herself worried that her bridegroom might recoil from her appearance although in the even the Prince behaved with style. She was, he said, much less fat than had been reported and in any case, "I find you adorable."