Katie Austin is celebrating a milestone birthday – in her swimsuit. In a new social media post the YouTuber daughter of fitness pro Denise Austin shows off her amazing body in a green bathing suit while vacationing in Kauai. "Woke up 30 flirty and thriving!!! feeling so much love today🫶 best day ever spent with the love of my life," she captioned the series of Instagram snaps. How does she keep herself fit and fabulous? Celebwell rounded up some of her top diet and fitness tips. 

Katie believes in mixing up your routine. Her workout app includes a variety of working, including HIIT, pilates, yoga, and dance. It is great for people "at all fitness levels because it provides customized workouts, variety, convenience, community, recipes, live workouts, and expert guidance. It can help you stay motivated, stay accountable, and achieve your fitness goals, no matter where you are on your fitness journey. All you have to do is press play and follow along!" she told E! News.

"Staying hydrated is important! So, I always carry a refillable water bottle like this one from Stanley to ensure I'm being sustainable and hydrating properly!" Katie told E! News. According to the Mayo Clinic, hydration is important for a variety of reasons. Water helps get rid of waste through urination, perspiration, and bowel movements, keeps your temperature normal, lubricates and cushions joints, and helps protect sensitive tissues.

To prepare for the big shoot, she "didn't do an entire overhaul of my lifestyle, but rather focused on things that were already important to me! I ate a balanced diet, worked out, and prioritized my mental health and routine!" she told E! News. "When it came to my diet, I didn't want to restrict myself from indulging in foods and my normal diet because I wanted to focus on the habits rather than cutting off 'bad foods' cold turkey. I ended up giving myself a 'kitchen curfew' of 8:00 PM, so that my body could digest dinner before bed, making it easier to get a better night's rest and to wake up more energized!"

One of Katie's top workout tips? "Find an activity you enjoy. If you hate running, you're not going to stick with a running program for very long. Instead, try different types of exercise until you find something you enjoy," she told E! News.  

"It can be helpful to have a workout buddy or join a fitness class or group. Having others to exercise with can provide motivation, accountability, and a sense of community," Katie told E! News.