That may seem like common sense, however, the logic lies in the fact watching what you eat works to improve your self-control so you are less likely to overeat.
The discovery was made by researchers at the University of Minnesota's Carlson School of Management.
Participants with both high and low self-control were observed to see what kind of eating behaviours they displayed.
Researchers wanted to see how satiation - the drop in liking that occurs with repetitive consumption - can work to lower people's inclination for junk food.
It was found that those with strong self-control who consumed unhealthy foods became satisfied faster than if they were eating healthy foods, resulting in them eating less.
Low self-control candidates were then asked to monitor each mouthful of food they consumed by counting every swallow.
The research, published in the Journal of Consumer Research, revealed that those with poor self-control became satisfied faster when they kept pace with the quantity of food they were eating.
As such, this means that people with low self-control can raise their willpower by tracking how much they consume, improving their chances of better weight management.
"People can essentially use attention for how much they are consuming instead of relying on self-control," said Joseph Redden, assistant professor of marketing at the Carlson School.
According to the expert, the issues does not really come down to willpower but merely the fact that some people are more inclined to stop enjoying themselves sooner than others.
He added: "Really paying a lot more attention to the quantity will lead people to feel satisfied faster and eat less."
Self-control appears to be integral to positive weight management, with a separate US study demonstrating that children who delay self-gratification have a lower risk of being obesity.