Shanna Fichera, 28, from Camarillo, California 

COURTESY OF SHANNA FICHERA

1. Start small. "I began walking or jogging for 15 minutes a day. I worked up to 30 minutes and then increased it again. It was a very gradual process."

2. Don't give up when your weight loss plateaus. "I remember hitting the first plateau and feeling so defeated, but you have to push through and keep putting in the effort for your plan to work. You can't get discouraged."

3. Be realistic about which habits need to go. "When I was heavy, I'd eat French fries every single day, plus carbs at almost every meal — like a sandwich for lunch or bread with pasta for dinner. A diet so heavy in fried food and carbs just isn't conducive to weight loss. To lose the weight, I went from three large meals a day to six small meals, mostly made of fresh vegetable salads with lean meats and nuts. And no more bread!"

Brianna Blank, 19, from Westbrook, Connecticut 

COURTESY OF BRIANNA BLANK

4. Find a healthy meal you like and eat it all the time. "In college, I researched the food available in the dining hall to find the healthiest options, settling on a turkey sandwich on whole wheat bread with mustard. I ate that for most lunches and dinners — and I was so focused on achieving my goals that it didn't even feel repetitive."

Maria Gordon, 28, from Upper Marlboro, Maryland 

COURTESY OF MARIA GORDON

5. Start with one small change. "I realized that a lot of sugar and calories that I consumed came from drinks, so I challenged myself to drink only water — no sugary drinks! — for 30 days. After just one successful week, I decided to add another challenge: to cut back on the carbs I was eating. When I did eat bread, I switched to wheat bread and when I wanted rice, I used brown rice."

6. Make your old favorites healthier. "I've always loved burger and fries, so I also started making healthier versions of foods that were familiar to me, like turkey burgers with wheat bread and sweet potato fries."

7. Prepare for heavy meals. "When I know I'm going out for dinner, where I'll probably want to eat extra calories, I eat lighter meals throughout the day, like a smoothie for breakfast and a salad for lunch."

Alyssa Ann Heidemann, 31, from Sioux Falls, South Dakota

COURTESY OF ALYSSA ANN HEIDEMANN

8. Switch out bad snacks for good snacks. "I used to snack on chips, candy bars, and other junk food throughout the day, but now I eat a set six times a day. My new snacks include protein bars or shakes, pistachios, celery sticks with PB2 (a lower-fat peanut butter), and low-fat string cheese."

9. Order smarter salads. "I cook most of my meals at home now but make healthy choices at restaurants like Applebee's if I go out. For instance, while I used to eat tacos, burgers, fries, and shakes, I now have salads without croutons and ask for a low-fat dressing on the side."

10. Cook for yourself. "I bake fish with olive oil or make a barbecue-style ground turkey. I eat green beans, carrots, celery, low-fat cottage cheese, string cheese, pistachios, olives, low-fat yogurt, grapes, and tangerines. And I usually don't feel hungry."