Inactivity, food availability and, of course, alcohol are contributing factors to the "fresher five" many first-year students experience.
Nutritionist Megan Somerville said a variety of factors contributed to a person's health and weight.
While not all students gained 5kg when they started studying, for some, weight gain was an issue.
Students were often more susceptible to poor health because of the change of environment experienced in their first year, she said.
Independence, a change of town and different people could all result in poor food and lifestyle choices which affected their health.
She encouraged students to think about what they were eating, and when, how much alcohol they were consuming and how much sleep they were getting.
While realistic about changing drinking habits of students, alcohol was "absolutely" a factor for weight gain and poor health.
It had "lots of calories and not much else", not to mention any fast-food bought on the way home from a night out.
Those living in halls could often find themselves offered plenty of food.
If personal checks were not put in place, overeating could occur, she said.
She recommended the "plate model" in which half of your plate was filled with vegetables, one-quarter with protein and one-quarter with carbohydrates.
"Fruit and veges are definitely your friends, especially in halls where it's all available."
One thing she did not advise skimping on was breakfast as it would "kick-start your day".
"Eating proper meals means you are less likely to snack," she said.
Exams and assignments also prompted an increase in snacking.
Rather than going for the high-fat, high-sugar option, Miss Somerville recommended air-popped popcorn and whole-grain or rice crackers.
For the sweet treat, a trim hot chocolate was a good way to satisfy a craving and get a calcium boost as well.
Overall, the key to staying healthy was to be active and eat a varied and balanced diet, she said.
Healthy lifestyle tips
- Vegetables are your friends. Aim for five servings of fruits and vegetables each day.
- Keep active. Go to the gym, play frisbee or walk with a friend.
- Watch your alcohol intake. It is full of wasted calories.
- Eat breakfast. It will kick-start your day, keep you going for longer and minimise snacking.
- Keep an eye on portion sizes: most foods will make you put on weight if you eat too much of them.
- A good guide to use is your hand. Think about a handful of rice or pasta, and the size and thickness of the palm of your hand for a piece of meat.