Your friend just ordered a steak, and you feel silly going with a salad for dinner, so you chime in, “Make that two.” Sound familiar? People tend to mimic each other’s eating behaviors, even down to taking bites of food at roughly the same time, according to a study published in the online journal PLoS One.

If you’re trying to impress your dinner date, this effect can go even further. College students who identified themselves as having eager-to-please attitudes were more likely to eat M&Ms — and take more of them — when another person offered them the treat, according to a study in the Journal of Social and Clinical Psychology.

6. No breakfast

People who miss their morning meal are 4.5 times more likely to be obese, according to a study in the American Journal of Epidemiology. Researchers suggest that forgoing meals slows down your metabolism, makes you hungry, switches your body into fat-storage mode and ups the odds that you’ll overdo it at your next meal.

In a University of Missouri study, teens who ate a 500-calorie breakfast that included cereal and milk every day for three weeks reported feeling less hungry when lunchtime rolled around compared to those who skipped the meal.

7. Scarfing it down

Grabbing a bite before rushing into a meeting may ward off an afternoon junk food craving, but if you scarf it down, it might not satisfy you the way it should. When you eat too fast, your stomach doesn’t have time to release the hormones that tell your brain you are full, according to a study in the Journal of Clinical Endocrinology & Metabolism. The longer that study participants spent eating a bowl of ice cream, the fuller they felt afterward.

8. Tiny treats

A small “fun size” candy bar may be worse for your waistline than you think. When high-calorie snacks come in small packages, people tend to eat more of them than when they come in bigger sizes, according to a Journal of Consumer Research study. Researchers say petite packages help people give into treats in the first place. Plus, single-serving snacks are usually sold in multiples, making it hard to stop at just one.

9. Burnout

An overbearing boss or heavy workload could impact your eating habits, according to research published in the American Journal of Clinical Nutrition. Among 230 women studied, those who felt burned out at work were more likely to report emotional or uncontrolled eating compared to those who were satisfied with their jobs.

10. Diet soda

The can says “diet,” but your favorite zero-calorie beverage may actually help you pack on pounds. Blame sugar substitutes, which mess with the brain’s ability to control how much you need to eat, according to a recent Physiology & Behavior study.

The brain uses a learned relationship between sweetened foods or beverages and the calories they provide to help regulate food intake, according to researchers at University of California-San Diego and San Diego State University. Routinely drinking diet soda throws off the brain’s sweet sensors, as you’re consuming something sweet, but your body’s not getting the calories it expects. Once confused, the brain stops associating sweets with having calories and your control around sweet-tasting foods starts to weaken.