Weight problems may begin earlier than we’ve thought. In fact, they can start in infancy.

The rise in child and teen obesity is well-documented. It's also a source of medical concern. More and more children are suffering from adult-type consequences of being overweight, such as high blood pressure, metabolic syndrome, and type 2 diabetes.

It has also become clear that children who are overweight when they are young are far more likely to become overweight and obese adults, making it all the more important to figure out what it is that makes some children prone to overeating, while others seem to have more moderate appetites and eating habits.

The findings make clear that as important as it is for babies to eat well and have plenty to eat, some children can get into a pattern of over-consumption that can bring on weight problems from an early age.

Overeating appears to take root in infancy in many people, and two studies published recently in JAMA Pediatrics suggest that two features of appetite are particularly associated with obesity, making some infants more food-oriented than others.

One, food responsiveness (FR), is the degree to which exposure to food — seeing it, smelling it — stimulates a person — or baby — to eat.

The other, satiety responsiveness (SR), measures how quickly a person's body signals they are no longer hungry after eating. Low SR means that it takes longer or more food for a person to feel satisfied or full from eating.

People — including babies — who want to eat when in the presence of food and those who are slower to register that their bodies' have had enough food tend to gain more weight and have a higher body mass index.

In the first study, researchers looked at the impact of FR and SR on weight gain over time. They followed non-identical twins who were very different with respect to appetite (with measurable differences in SR and FR). The pairs of twins were living in the same homes, exposed to the same social, nutritional, and parenting influences.

The babies’ weights were tracked for 15 months to determine what effect their appetite differences might have on their weight.

Infants with higher food responsiveness and lower satiety responsiveness grew faster than their twins. The researchers concluded that as early as birth to 15 months, hearty appetite played a major role in childhood weight gain.

Genetics seem to influence satiety responsiveness, according to the second study, which found that a sensitivity to when one is no longer hungry is a highly heritable factor in obesity. When body signals that one is no longer hungry are slow to register, and a person lives in an environment that has plenty of food readily available, they tend to overeat and gain weight.

Helping Eager Eaters Slow Down

One of the main goals of well child visits through the first years of life is to record a child's physical development — particularly his or her height and weight. Each age and stage of infancy and toddlerhood has caloric guidelines, as well as important recommendations about the types and quantities of liquids and solids (such as breast milk, formula, cow’s milk, juice, cereals and pureed table foods).

These feeding guidelines are based on the nutritional needs determined to provide optimal physical, neurological, and emotional growth and development and the evolving ability of the infant to tolerate a variety of foods. The guidelines don't factor in babies' different levels of food interest, but perhaps they eventually will.

Parents could limit portion sizes to give over-eager eaters a chance to realize they are full.

When a child's growth puts them at the extreme upper end of growth chart norms, it is time to take a look at his or her eating habits.

The findings make clear that as important as it is for babies to eat well and have plenty to eat, some children can get into a pattern of over-consumption that can bring on weight problems from an early age.

If parents and doctors are able to identify those infants with low SR and high FR (from their early nursing or bottle-feeding behavior), they could take steps to help babies avoid what is triggering their overeating and put an early dent in the rising tide of childhood obesity.

For example, parents of children who are always ready to eat might want to keep food out of sight until meal or snack time, so that the visible presence of food doesn't stimulate the desire to eat. They could also limit portion sizes, thus giving children a chance to realize they are full.

Based on the new research studies if you have a baby or child who is a hearty eater, who tends to eat without stopping as long as food is presented to them, and who consistently is in the 90th percentiles for their height and weight, you may want to ask your pediatrician if minor restrictions in making food available to the child might not be a good idea.

Proper nutrition is extremely important to children's development, so restricting the amount of food a child eats should always be done with the guidance of your child's doctor, but these studies suggest it could help prevent a lifetime of weight problems.