Remember when you were a teenager and you could eat a huge bowl of cereal or two-minute noodles before dinner, and still be able wolf down everything (and stay scrawny)? Those were the days.
Comparing this to our adult eating habits and metabolism, it's easy to see our nutritional and energy needs do change depending on our age.
Eating right for your age can help support our body's functions and overall health, Jessica Spendlove, accredited practising dietitian and athletic performance dietitian, told HuffPost Australia. But don't worry, it's not as restrictive or hard as it sounds. It's just about making sure you're getting enough of the right vitamins and minerals.
"What our bodies need changes as we move through different life stages, so as you age there are key considerations you need make in regards to your nutrition and health," Spendlove said.
"Eating a balanced diet as well as exercising regularly plays a big part in how well (or not so well) we age."
How to eat right for your age
"There a number of factors which change as we age, including metabolism, muscle mass, hormone levels and nutrient needs," told HuffPost Australia.
Childhood and adolescence
To ensure children and adolescents are receiving the nutrients needed for optimal body function and growth, it's important they meet daily intake requirements for fruit, vegetables, whole grains, protein and calcium. This includes ½-2 serves of fruit, 2-5 serves of vegetables, 4-7 serves of grain, 1-2½ serves of protein and 1-3½ serves of dairy or dairy alternative -- depending on the age.
"Calcium requirements are at their highest for men and women during adolescence when we are developing peak bone mass, and then also later in life when bone mass is naturally declining. The recommended daily intake of calcium for boys and girls aged 12–18 is 1300mg," Spendlove said.
"Iron requirements increase for women when they begin menstruation. They increase from 9mg to 18mg per day, so focusing on adequate iron-rich foods is important."
20s and 30s
When we reach adulthood we need to slightly increase intake of fruit (two serves per day), vegetables (5-6 serves), grains (4½-9 serves), protein (2-3½ serves) and calcium (2½-4 serves).
"Bone density continues to grow until late 20s so adequate calcium intake is important across your 20s to optimise bone health, which is important for preventing osteoporosis later in life," Spendlove explained.
The recommended daily intake for calcium in adulthood is 1,000mg per day.
"Your 20s and 30s are often a busy time in life and eating right can drop down the priority list. Focusing on eating adequate fruit, vegetables and fibre intake is important for health both now and also long term."
Nutrition needs for pregnant and breastfeeding women do change quite significantly.
"For a women looking to fall pregnant, adequate folate (also known as folic acid) is important both before and after conception in protecting your baby against neural tube defects," Spendlove said.
Iron requirements peak for women during their childbearing years, so ensure you're getting 18mg per day.
"Iron deficiency continues to be a problem for women in their 20s and 30s, so focusing on consuming iron-rich foods such as red meat three times a week will assist in the prevention of this," Spendlove said.
"Other iron-rich alternatives are foods such as legumes, lentils, soybeans, tofu, tempeh and fortified whole grain products."
Protein, zinc, iodine, selenium, omega-3s, B12 and vitamin C requirements also increase when pregnant and breastfeeding. If in doubt, always check with your GP.
40s and 50s
Optimising nutritional intake and food diversity is important in our 40s and 50s. It's also a time where we need to be particularly mindful of our weight.
"This is a period in most people's lives where they are most at risk of gaining weight due to a variety of reasons, including a reduction in metabolic rate," Spendlove said. "Focusing on meal portions, lower energy foods and including regular exercise rather than ceasing it can all help."
Eating lots of fruit and veggies -- as well as essential fatty acids from oily fish, avocado, nuts and seeds -- is also crucial to help support the body and brain.
"Focusing on consuming foods rich in antioxidants is important -- this means eating a variety of different coloured foods from the various food groups," Spendlove said.
"Diets rich in antioxidants can help protect against heart disease, certain cancers and Alzheimer's."
It's also important that we continue (or begin) resistance training and eat enough protein throughout our 40s and 50s.
"As we age we organically lose muscle mass. This can be minimised or prevented using targeted nutrition and training strategies, including adequate protein intake (as well as the timing and distribution) and undertaking resistance training."
Many women will go through menopause during this time which affects calcium requirements.
"When a women goes through menopause significant changes occur as a result of decreased oestrogen levels. These changes can include decline in libido and increased risk of osteoporosis and heart disease," Spendlove explained.
"Decline in oestrogen accelerates the loss of calcium from bones, which increases the risk of osteoporosis or brittle bones. To counteract this, it is important to consume at least three serves of calcium-rich foods per day."
Over 60
"As we get older we often need less energy intake as most people are less active than when they were younger," Spendlove said.
"Focusing on adequate protein is important in this age group as it has been shown to decrease body weight and fat mass, retain lean muscle mass and provide greater satiety (feeling of fullness)."
Again, making sure we're getting enough calcium per day is incredibly important.
"The recommended daily intake for calcium for women 51 years and older, and men over 70 years of age, is 1300mg."
What about exercise?
"Being active is important for all ages," Spendlove said. "Australian guidelines are now focused on both encouraging physical activity and limiting sedentary behaviour."
Exercise guidelines:
Children (5-12 years) and teens (13-17 years) should accumulate at least 60 minutes of moderate to vigorous intensity physical activity every day. They should do a variety of aerobic activities and engage in more activity for additional benefits.
Adults (18-64 years) should accumulate 2½-5 hours of moderate intensity physical activity or 1¼-2½ hours of vigorous intensity physical activity (or a combination of both) each week.
Older adults (65 years and older) should accumulate at least 30 minutes of moderate intensity physical activity on most, preferably all, days.