They’re both known for their trim physiques and figures, but even Pippa Middleton worried about her older sister Kate before her 2011 wedding to Prince William, when the Duchess of Cambridge began to exhibit an even more slim look.

According to a report from that year resurfaced by Express UK, Middleton’s sister was so worried about her sister and that she wasn’t eating enough that she bombarded her daily with a series of calls to check-in and make sure everything was okay.

“Pippa was so worried about her sister’s ever-shrinking size frame, she called up to five times daily to check Kate was tucking in,” correspondent Emily Hall said at the time. “Kate became stricter with her diet at the end of last year to look super-slip walking up the aisle.”

“She swapped her usual treats of pizza and Haribo for low-fat mini-meals and began running to tone up,” she added.

Concern also stretched to her future husband, who knew she was taking on a lot of new responsibility and pressure as his wife, but all the worries seemed to not be necessary because while Middleton was restrictive, she was following the plan of a specific diet.

The Duchess used the low-carb French diet known as the Dukan diet as she prepared for her wedding, and the process consists of four phases. The first phase, known as the “attack,” consisted of Middleton eating only pure protein, before going to the Cruise phase, which added vegetables to the diet as well. The other two phases were the Consolidation and Stabilization phases.

Middleton’s weight has often sparked concerns because of her frame because while is reported to be a size 6, some do believe she is actually much smaller than she appears in photos because the camera is known to add 10 pounds.

She also faced criticism for bouncing back to her pre-baby figure quickly after all three of her pregnancies, while her sister-in-law, Meghan Markle, appeared to lose weight much more gradually.

Pippa Middleton, Kate Middleton
Kate Middleton and Pippa Middleton are pictured talking in the Royal Box before the men’s singles final match between Britain’s Andy Murray and Switzerland’s Roger Federer on Centre Court on day 13 of the 2012 Wimbledon Championships tennis tournament at the All England Tennis Club in Wimbledon, southwest London, on July 8, 2012. Getty Images/Leon Neal/AFP