This article originally appeared on Time.com. 

Losing weight is tough, both mentally and physically. New science shows that when the body starts to lose substantial amounts of weight, it fights viciously to gain it back. But despite the biological roadblocks, plenty of people are successful at losing weight and keeping it off over the long term.

But how? As part of its recent exploration of the new science of weight loss, TIME asked 9 weight loss and obesity experts their best advice for people who are trying to lose weight. Here are their top tips for what works when it comes to slimming down.

Cut out soda

“Avoid all sugary drinks, as they provide ’empty calories’ that don’t fill you up. The sugar may uniquely act on the liver to produce belly fat.”

—Dr. Dean Schillinger, chief of the University of California, San Francisco Division of General Internal Medicine

Don’t focus on calories

“The ‘calorie in, calorie out’ approach fails, because it disregards how food affects our hormones and metabolism. Pay attention to food quality.”

—Dr. David S. Ludwig, professor of nutrition at Harvard Medical School

MORE: You Asked: What’s the Best Way to Lose Weight?

Keep it basic

“The simple message is to eat a healthful diet and to engage in more moderate-to-vigorous physical activity. The challenge is how to actually accomplish that in an environment that seems to push us constantly in the wrong direction.”

—Dr. Stephen R. Daniels, pediatrician-in-chief at Children’s Hospital Colorado

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Adjust your goal weight

“Aim to achieve and improve health and reach a psychologically ‘happy weight,’ not an unrealistic ‘ideal’ weight that may be impossible to reach for most.”

—Dr. Jaideep Behari, associate professor of medicine at the University of Pittsburgh School of Medicine

Commit to change

“People need to have the mindset of someone who is ready and willing to make some permanent changes in the way they live. A number of treatments can create short-term weight loss without a great deal of effort from the person, but they don’t allow for long-term weight loss.”

—Dr. Michael Jensen, obesity researcher at the Mayo Clinic

MORE: ‘I Swallowed a Balloon For Weight Loss and Lost 40 Lbs.’

Eat delicious food

“You need a program that satisfies hunger and has good food so it doesn’t feel like a diet. Hunger erodes willpower, and that’s the reason most diets fail.”

—Susan B. Roberts, professor of nutrition at Tufts University and founder of iDiet

Recruit support

“Make small changes that stick, make changes as a family and keep it positive.”

—Dr. Stephen Pont, medical director of the childhood obesity center at Dell Children’s Medical Center

Get educated

“The culprit is not bad choices by individuals. It is the toxic food environment in which calories are ubiquitous. Until the food environment changes, everyone must become aware of the calories they consume, especially those from beverages, sweets, and other calorie-dense foods.”

—Dr. Lawrence J. Appel, director of the Welch Center for Prevention, Epidemiology, and Clinical Research at Johns Hopkins University

MORE: If You Want to Lose Weight, Don’t Eat Out

Make friends with moderation

“A person can eat almost anything they want, but the portion size has to be appropriate. For example, eat dinner on a salad plate rather than a dinner plate to cut the portion size in half.”

—Melinda L. Irwin, professor of epidemiology at Yale School of Public Health