Doctors and dieticians can provide important facts about shedding fat—what to eat, what not to eat, how often to work out—but if you really want to know the most effective ways to lose weight, your best bet is to go straight to the source: those rare individuals who have managed to drop significant pounds while avoiding the dreaded regain.

Below are the top 5 knowledge nuggets shared by our most successful clients. Embrace their weight-loss wisdom, and you’ll be well on your way to a smaller jean size.

1. The time is now. Plenty of clichés speak to the importance of taking action—“carpe diem,” “there’s no time like the present,” “don’t put off to tomorrow what you can do today”—and with good reason. Throughout our careers as trainers and nutritionists, we’ve seen firsthand how ditching the I’ll-start-my-new-diet-on-Monday attitude is key for long-term weight loss. If you’re truly ready to make a change, do it right away—not tomorrow, not on the first of the month, and not on New Year’s Day. Our tip: circle today’s date on your calendar and start taking the steps to make the change happen immediately.

2. There’s no such thing as perfect. Slipups are part of any worthwhile journey, and weight loss is no exception. Some days, your get-fit plans will go smoothly and you’ll effortlessly do everything “right,” while other days you’ll face temptations and obstacles, and, yes, inevitably make some mistakes. But that’s a good thing! If you’re making mistakes, you’re trying, and if you’re trying, you’re learning. Weight-loss winners don’t beat themselves up. They pick right back up where they left off at their next meal.

3. The small stuff is the big stuff. People who successfully drop pounds tend to track their progress, but we’re not just talking about stepping on the scale. “Little things” like walking up a few flights of stairs without getting winded, bringing your belt in an extra notch, or noticing an improved complexion after eating and sleeping well for several months are what losing weight is all about: good health. Remember to reward yourself for the small achievements, as well as the large ones.

4. You’re only as healthy as the company you keep. How much easier is it to hit the gym after work when your friend offers to go with you, as opposed to begging you to bag on your workout and hit happy hour instead? Surrounding yourself with people who are either already living a healthy lifestyle or working towards that goal can play a major role in helping you achieve your own goals. Find like-minded people who support your healthy lifestyle: Join a running club, find a hiking meet-up, or take cooking classes.

5. Food is AWESOME. You don’t need to give up your love for food to be slim! Successful weight losers ditch “diet” foods in favor of whole foods, which provide tons of flavor, along with healthy nutrients. “For lasting weight loss, it’s really important to focus on clean and natural foods. Cut out processed and packaged foods and fill your body with what it needs most: real, nutrient-rich foods. Eat with the season and you can’t go wrong,” says weight-loss expert and dietitian Heather K. Jones. Right now we’re loving these seasonal picks:

California Grapes

In season through January, grapes are packed full of important nutrients like polyphenols, an antioxidant that’s been shown to promote overall health. Check out Heather’s delicious and healthy California Grape and Avocado Salad here.

Pumpkins

With just 40 calories, a whopping 5 grams of fiber, and a hefty dose of beta carotene in every half-cup serving, you can’t go wrong with pumpkin. And it’s not just for the sweet stuff, either. Try out this delicious savory pumpkin pizza to get your fill!

Apples

Fall’s signature fruits are loaded with flavonoids and fiber, and their phytonutrients and antioxidants have been linked with a reduced risk for cancer, hypertension, diabetes, and heart disease. Our homemade apple butter is our go-to apple recipe.

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Tammy Lakatos Shames and Elysse “Lyssie” Lakatos—otherwise known as the Nutrition Twins—are registered dietitians, certified personal trainers, and authors of The Nutrition Twins’ Veggie Cure: Expert Advice and Tantalizing Recipes for Health, Energy and Beauty