The statistics are shocking. Two-thirds of U.S. adults and (depending on how you count) at least a fifth of children are now overweight or obese. Nearly everyone is either struggling with their own weight or has friends and relatives who do so. And the problems are not going away: medical complications due to years of excess poundage are only now starting to emerge, and for the first time children are being diagnosed with the unthinkable ¾ diseases like Type 2 diabetes, that previously were seen almost exclusively in middle-aged adults and the elderly.

Weight problems are a tough burden for kids, but fortunately there is much we can do as parents to prevent and treat emerging problems. In my opinion, the first and most important thing parents can do is help themselves. I realize this might sound counterintuitive, but think about it this way ¾ even if you feel that genes are a big part of the problem in your case, those genes express themselves through things like giving in to temptations and overeating. Kids whose parents struggle with weight live in the same challenging environment. And probably most important of all ¾ children whose parents struggle unsuccessfully with their own weight don’t have a role model of a loved adult enjoying healthy foods without battling to keep calories down.

Our Five Food Instincts

So how do you get your own weight under control, once and for all? The first thing to accept is that it really isn’t your fault if you have gained weight—our food environment is just that toxic. The second thing to accept is that dieting doesn’t have to be rocket science; with a good approach and attitude most people can lose weight and do well. At Tufts University in Boston, where I direct a research program devoted to improving methods of weight control for the toughest cases, at least 85% of our volunteers lose at least 10 pounds and keep it off for at least a year, and some people have lost an amazing 27% of their weight. They confront issues like plateaus, cravings and hunger with techniques that allow them to work through them and be successful.

Based on research in my lab and other research by weight control experts worldwide, I have come to realize that successful weight control starts with understanding that we, as humans, are hardwired for just a few things that relate to food. We have inbuilt mechanisms that make sure we eat enough food of the right kinds to keep us safe. And because instincts are basic to survival, they work on a subconscious level and are activated by powerful signals from our body and senses that make us feel an urgent need to eat. Of course, we can’t control them: they are too powerful! But once we understand this and learn how to control the signals themselves, we can get our food instincts to work for us, not against us, in the battle against excess fat.

Here’s how it works. Five basic food instincts stand out as being responsible for our continuing survival against all odds. We know this from studying human history and from all the consistent findings of modern research into our own eating patterns. Although nutrition research is well known for having almost as many opinions as nutrition scientists, when it comes to the topics that I’m calling our food instincts, all nutritionists agree that they are tremendously important and influence how and what we eat. Today, our food instincts can be our downfall, and the downfall of our children, unless we take a close look at them and decide to work with them rather than against them. Our instinctive eating behavior falls into these categories:

Hunger We need to satisfy our hunger. We like feeling full. We see this instinct in newborn infants, and we know this is not something they have learned; it is an innate need that will help to ensure their survival.

Availability We eat just because the food is there. And—here’s the thing to watch out for—we want to eat more when more food is there.

Calorie density We love to eat and we love food, especially when it’s loaded with calories. This is true in every culture around the world.

Familiarity We enjoy eating foods that are familiar to us. We associate these foods with feeling safe and comforted, and we have triggers that can drive us to eat them again...and again.

Variety We are instinctively attracted to a variety of foods, and we eat considerably more when we’re presented with more choices.

Our Availability Instinct

Bad Popcorn in Large Buckets

In a study at Cornell University, 158 moviegoers were offered free popcorn in return for answering some questions about the theater after the movie. Half got fresh popcorn in 120-gram (4-ounce) or 240-gram (8-ounce) buckets. The other half got stale popcorn in the same-size buckets. After the movie, the containers were weighed to see how much everybody ate. The moviegoers who were given a large bucket of stale popcorn ate almost as much as those who were given a smaller bucket of fresh popcorn. This doesn’t mean they liked it. They just ate it because it was there.

Average amount eaten (in grams) Small Size Large Size
Fresh popcorn 59 86
Stale popcorn 38 51

When you open a bag of potato chips, do you eat more than you intended? Or if you stick your hand in the cookie jar, do you find you have had several, not just one, before you can stop? If so, it’s because your availability instinct has taken charge and you just can’t help yourself. It’s a little recognized fact that having food readily available can trigger hormonal and nervous system activity that makes us hungry—even if we’ve just finished a fancy five-course dinner. Still more surprising is the recent finding that the available food doesn’t even have to taste good! We’ll wolf it down as if we haven’t eaten for days. It turns out that we’ll even overeat stale peanuts if there’s a big enough bowlful within easy reach.

Our instinct to eat just because it’s there developed thousands of years ago and is a major cause of weight gain today in both adults and children. As members of the species now called Homo sapiens, we had to cope with the changing circumstances in the world around us. This was essential for survival, and the most successful survivors were those who ate whenever food was available. The problem for us today is the abundance of available food, especially if it’s food that we know and like.

Bigger portions are a further problem because even more food is in front of you when you sit down to eat, so your availability instinct keeps you from putting your fork down when you should feel full. After summarizing all the research studies on portion size and food consumption, my lab calculated that for every 1,000 calories added to your plate on top of what you need, you’ll most likely end up eating about 190 of them. That doesn’t sound like a lot, but continuing to do this just once a day for a year can cause a weight gain of many pounds (at 190 calories per day, you would gain almost 20 pounds in a year!). It’s easy to blame it on mothers for telling us to clean our plates, but most of us do this pretty instinctively with no encouragement at all. And when portion sizes are routinely several times what we actually need, the internal signals that we rely on to tell us when to stop eating become confused. In a study conducted by Brian Wansink at Cornell, soup bowls were refilled surreptitiously so that none of the participants knew how much they were consuming (because the levels in the bowls never went down). The surprising result was that, on average, the participants ate 76% more soup but estimated that they had eaten only 5% more!

Gulp, Gulp, Gulp. Large portions also encourage what I call the Gulping Syndrome. Faced with a large plate of a favorite food, we tend to take bigger bites than we normally would and swallow them quickly without realizing what we’re doing. Often we prepare the next mouthful on our fork while we’re still swallowing the previous one. Studies show that even preschoolers will take larger bites if they’re presented with large portions of food.  Instinctively adapting to their environment, they open their mouths wider and swallow faster.  Preschoolers!!

Here’s why the Gulping Syndrome is such a problem. When we take big bites of food, we don’t give ourselves time to realize that we’re getting full. This means we end up eating more simply because it takes longer for us to feel satisfied.

The Importance of Taste

What we think of as taste is really 90% smell. In the mad rush of gulping down large portions, fewer of the volatile smell chemicals in food get to activate the 10 million olfactory receptors located in our nose. This loss of intense taste when large portions are eaten in big bites is probably why small portions have been found to be just as satisfying as large ones. Studies show that people given small bowls for ice cream eat about a third less than if they’re given large bowls but feel equally satisfied.

Be the Boss

Who’s in charge of your food environment? You are. So it’s up to you to get rid of what tempts you (and your children) and to stock good alternatives. This might sound like a small thing, but I promise you it can make a big difference. In fact, some families may find this is literally all it takes for everyone to lose a few pounds and keep them off. According to my research, being susceptible to foods lying around at home can cause a massive 40 pounds of weight gain between the ages of 20 and 55, so changing this one thing is really important! Below are some really easy but powerful suggestions for improving your home environment so that you can eat better – and, over time, your child will follow along.

  • Put these great weight control foods where you can see them and get to them easily.

    • Arrange fruit in a bowl, on the kitchen counter.
    • Keep a bowl of cut-up celery, red peppers and other vegetables in the fridge, ready to put out on the counter for snacks and before dinner.
    • Buy pre-washed salad greens and have a variety of tasty dressings available so that salad is instantly available and interesting every day.
    • Stock some high fiber cereals. (Trader Joe’s High Fiber Cereal, Fiber One by General Mills and All Bran Extra Fiber by Kelloggs are great choices.) Served with milk (the low/non-fat milks that are enriched to taste like full-fat milk are a calorie-wise choice), they can be mixed with regular cereal for older kids who get hungry, and adults can have one or two servings a day to increase fullness and satisfaction.
  • Get rid of unhealthy foods.

    I know this isn’t easy, but just do it. Clean out your kitchen cupboards and check under the bed and any other place where you might have hidden stuff that tempts you. Toss out all those half full bags of chips and crackers and the leftover cake from last night’s party.

  • Write down everything you eat.

    Keeping an honest record of exactly what goes into your mouth is an invaluable tool when it comes to weight loss. Food is everywhere, tempting us all the time, and we can easily think we’re eating a lot less than we really are. It’s even possible to overeat when we eat nothing unhealthy. You may well discover that casual eating is your diet destroyer. At Tufts, we find that many volunteers cut down on portion size and casual eating soon after they start recording everything they eat. In fact, writing down what they eat improves their food awareness to such an extent that quite a few of them begin to lose weight even before their diet starts.

  • Make high-calorie foods less user-friendly.

    The less often you see large amounts of foods like nuts, cheese and chocolate, and the harder they are to get at, the less tempted you’ll be to overeat them. You might, for example, limit yourself to grated Parmesan cheese (not the delectable soft blocks that you can cut nice slices from). In the chocolate department, try buying a chunk of Belgian chocolate and storing it in the refrigerator so that cutting off a piece to eat is a job in itself (and requires care!). Incidentally, most people are less likely to overeat dark chocolate than milk chocolate, so stick with the dark if that helps. At mealtimes, don’t put anything on the table that you and your family shouldn’t eat in unlimited quantities. Leave entrée dishes on a side table or countertop nearby. Amazingly, research has shown that just those few feet between the table and counter means that people will eat less. And put less food on your plate, and cut it up before you start eating. The more small changes you can make to control the food environment around you when you’re not eating at home, the easier it will be to avoid backsliding.

    In Praise of Small Spoons

  • Limit restaurant meals.

    Eat at home as often as possible, and avoid takeouts. Restaurant meals have more calories and less fiber than home-cooked meals, and the more often people eat out, the heavier they tend to be. In a study I did of 73 men and women from age 19 to 80, those who ate in restaurants only three times a month on average had fully a quarter less body fat than those who ate out once a day. It didn’t matter where they ate; it was the frequency of restaurant meals that mattered. Partly this is because of the huge portions that restaurants serve: chefs tend to have a very distorted view of what normal portion size should be: one study reported that the portions they considered “normal” were two to three times the size recommended by the U.S. government!

Dr Roberts is author of The Instinct Diet: Use Your Five Food Instincts to Lose Weight and Keep it Off (Workman Publishing 2008). For more details on getting started with instinctive eating for the whole family go to