Jessica Simpson Says No-Prenup Marriage To Nick Lachey Was Mistake: Her Weight Loss Tips — Jessica Simpson’s clothing line boasts annual revenue of $1 billion. (Photos: Instagram)

Jessica Simpson is a fashion mogul with a clothing line posting annual sales of $1 billion. Jessica has made few money mistakes during her lucrative career, but said her biggest financial mistake was her first marriage.

“The biggest money mistakes? For some reason I thought of my first marriage!” Jessica told CNBC.

Simpson was married to singer Nick from 2002 to 2006, during which time they starred on their own MTV reality show, Newlyweds: Nick and Jessica.

Jessica was forced to pay Nick alimony after their divorce because the couple did not sign a prenuptial agreement before marriage.

When they married, Lachey was far more successful than Simpson, and Jessica’s then-manager (dad Joe Simpson) insisted Jessica not sign a prenup.

When the couple divorced in 2006, Jessica’s net worth dwarfed Nick’s, so she wound up paying spousal support.

Lachey is now happily married to TV star Vanessa Minnillo, with whom he has two children. Jessica is married to former NFL star Eric Johnson, with whom she has daughter Maxwell, 3, and son Ace, 2.

Jessica is now a fashion icon, thanks her clothing and accessories lines, which include handbags, apparel, jewelry and swimsuits.

Simpson, who has maintained her 70-pound post-baby weight loss since 2013, is her own best advertisement for her fashion brand, which she says fits women of all sizes.

The busty 5-foot-3 Simpson lost 70 pounds six months after giving birth to son Ace Knute in June 2013. Simpson lost the same amount of weight after giving birth to daughter Maxwell in May 2012.

Simpson, a rep for Weight Watchers, has credited a low-carb diet and rigorous daily workouts for her dramatic weight loss, Examiner reported.

Jessica’s low-carb diet typically features a mix of high-quality proteins like salmon and chicken and fresh vegetables and salads. Simpson also avoids processed foods and limits sugar.

Low-carb diets like the Atkins, Paleo and ketogenic plans promote rapid weight loss by encouraging the body to burn body fat for fuel, said obesity expert Dr. Eric Westman, co-author of Keto Clarity.

A Canadian mother-daughter duo recently credited a low-carb, high-fat ketogenic Paleo diet for their combined 110-pound weight loss.

ketohybrid laura veronica childs weight loss — Veronica and Laura Childs have lost a combined 110 pounds with a low-carb, high-fat ketogenic Paleo diet. (Photos: L. Childs)

Laura Childs and her daughter Veronica lost 65 pounds and 55 pounds, respectively, several months after embarking on a low-carb, high-fat diet. They have maintained their weight loss for more than a year.

Laura and Veronica chronicled their stunning weight loss in their book, Low Carb High Fat No Hunger Diet: Lose Weight With A Ketogenic Hybrid. The Childs’ book details their prior weight struggles, the science behind ketosis and 75 delicious, easy low-carb recipes.

jessica simpson weight loss swimsuit — Jessica Simpson said gaining 70 pounds during her pregnancies was depressing and made her insecure. (Photos: Instagram)

For exercise, Jessica Simpson walks a minimum of four to five miles every day (or 8,000 to 10,000 steps) and does yoga.

Simpson also works out at the gym for 45 minutes, four days a week, with her longtime trainer Harley Pasternak, creator of the 5-Factor Workout DVD.

Pasternak and Jessica typically work out at the gym four days a week, combining 10 to 20 minutes of cardio exercise, 20 to 30 minutes of resistance training, and lots of flexibility moves.

Harley said the foundation of Jessica’s workout routine is walking. Pasternak, author of 5 Pounds, also trains Lady Gaga and Kim Kardashian.