Are you sick of bouncing back and forth between inspired spurts of deprivation and weeks of indulging bad habits? Dr. Terese Weinstein Katz, founder of the Eat Sanely program, explains why we eat (or fail to eat) to extremes and how to break the cycle.

Q: What is eating sanely?

A: I define sane eating as "eating that maintains a healthy enough weight, for good, without extreme dieting, and with peace of mind." That means that, most of the time, your eating does not involve extreme over or under-eating. It means that you don't live part of your life "on a diet" and part of it not. And it means that you're not constantly worried or guilty about what or how you're eating. In short, you're eating in a way that you can live with, day in and day out, year in and year out, and that maintains a weight that's acceptable to you and doesn't cause health problems.

Q: Why do so many of us have a tough time eating sanely?

A: Most of us do indeed have a hard time eating sanely for a variety of complicated reasons. First, we live in a world where fattening, unhealthy foods are available to us in overabundance. We are biologically geared to overeat these foods (they signal the oldest, most primitive parts of our brains - "more, more, more" - as if we need to prepare for famine). And food companies capitalize on this by engineering "hyper-palatable" foods that trigger that "more, more, more" response.

Next, food has strong emotional associations that easily hook into our needs for comfort and calming. So, it's easy to start seeking food when we're emotional off balance or stressed. People feel emotionally off balance or stressed a lot in our modern world. Eating habits can be particularly hard to change, for both biological and emotional reasons. So, we set out to eat differently, struggle with it, give up. We dislike the weight we put on, try again, and then give up again. We start to think of these efforts as temporary. Diet plans that make you feel bored or starved contribute to that idea too. So, the idea of changing once and for all continues to elude us.

Q: What most commonly sets us up for failure when it comes to healthy eating?

A: I think all of this sets us up for failure: the foods we face, our temporary "diet" mentality when we face the prospect of changing how we eat. It's an uphill battle, to be sure. Probably the biggest set-up is the idea that it can happen easily or quickly. Dietary overhauls that stick, that last for the long term, take time. They take trial-and-error readjustments, a lot of patience and self-forgiveness. Truly, both your mind and your body need to change. That doesn't happen after a couple of weeks of reducing your carbohydrate intake, for example.

Q: Do you think we often have an all-or-nothing attitude when it comes to diet?

A: Most of us, absolutely, have an all-or-nothing view of dietary change. We're on a diet or off a diet. And in the back of the mind, then, is the idea that "soon the diet will be over....thank goodness." I think that common sense, and now plenty of scientific research, tells us that changing how you eat for a temporary period will never stabilize weight. People usually regain more than they've lost when they "diet." The only thing that works is a permanent change in how you eat, day and day, for good.

Q: What does eating sanely look like in practice?

A: Here are some statements that would be true if you were to eat sanely:

• I pay attention to what I eat but don't spend too much time worrying about it.
• I am more or less satisfied with my weight.
• Mostly I eat healthy food.
• I don't panic if I eat something "bad."
• If I mess up, food-wise, I get back on track the next meal, or the next day.
• I don't eat in secret or lie about what I eat.
• I can usually dine-out without overdoing it.
• I eat sweets and "treat foods" in moderation.
• I don't skip meals to manage weight.
• I know that keeping active helps my weight and my body.
• I eat unprocessed foods most of the time.
• I do not try to "purge" foods if I overeat.
• I know that few people can "eat whatever they want" without concern for weight, and I make choices accordingly.
• I often really enjoy my food, though I know that not every meal has to be great.
• It is OK to get hungry once in a while, though I rarely let myself become ravenous.

Q: What advice do you have for someone who wants to eat sanely?

A: If someone wants to start eating more sanely, I'd suggest taking a thorough look at how he or she is eating right now. Often it's helpful to write down exactly what you eat for a few days. Where are you doing well? Where are the spots needing change? If you can pick one or two goals (for instance, eating more green vegetables, replacing one sugary drink or treat with something better, eating more dinners at home....) and stick with these for two to six weeks, that's a great start. Even if your "sticking with" those goals is less than perfect, it's a good start. Then see if there's another goal to tackle. If you have a lot of weight to lose, you may need to be more aggressive than this, especially if your health is affected. However, in that case, I'd suggest working with a doctor, diet coach, or specialized therapist, because making changes you can stick with, while at the same time losing weight as quickly as your health requires, calls for a lot of support. It just does-it's not a matter of you being weak or lacking willpower.