A dietitian lost 20 pounds and kept the weight off for 9 years. She shared her grocery list staples from Costco.

• Buying weekly groceries on Sundays helped a dietitian lose 20 pounds and keep them off.
• Hailey Gorski's hacks include cooking a medley of vegetables that make it easy to create nutritious meals.
• Gorski's staples include a rotisserie chicken and cottage cheese.

Hailey Gorski lost 20 pounds in 2016 and building sustainable habits, like buying staple groceries on a Sunday and "ingredient prepping," have helped her keep the weight off since.

Gorski is a big fan of Costco, where she buys the protein, fresh produce, healthy fats, and high-fiber carbs, such as beans, that make up her meals.

While the 28-year-old dietitian based in LA doesn't meal prep, she stocks her kitchen with food that makes throwing together a balanced meal as easy as possible.

At the start of each week, for example, she roasts a medley of vegetables in the oven with avocado oil, salt, pepper, garlic powder, and onion powder, which she stores in the fridge. She adds the veggies to a range of meals, from salads to wraps and pasta sauce.

To remove any barriers that might prevent her from eating the nutritious food she has bought and prepped, Gorski puts the ingredients in a visible place in her fridge or store cupboard.

Another hack of hers is cutting stalks of celery, cucumber, and carrots into bite-sized pieces, ready to grab from the fridge and dunked into a cottage cheese dip as a high-protein snack. She'll also shred the meat off a rotisserie chicken to make it easier to use as an ingredient.

Here is her weekly grocery list:

Proteins:

• Greek yogurt
• Cottage cheese
• A protein-rich dip, such as hummus or tzatziki
• Turkey slices
• Ground beef
• Rotisserie chicken

Produce:

• Arugala
• Spinach
• Frozen berries
• Mushrooms
• Broccoli
• Red onion
• Asparagus

Fiber:

• Chia seeds
• High-fiber pasta
• High-fiber wraps

"I always bring it back to my default meals," Gorski said, because this can prevent us from overeating higher calorie convenience foods.

"This is something I always teach my clients too: the importance of having those default meals to remove that decision fatigue," she added.