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Can you have too much of a good thing?

We all know what’s good – but is more always better? HFG nutritionist Claire Turnbull investigates the occasions when healthy foods can cause an overload.

What happens if you eat too much?

Fruit is good for us, but for a healthy balanced diet a variety of different foods is best. If you regularly call two to three pieces of fruit a meal, or rely solely on fruit for a snack, you may be getting your carbohydrates mainly from fruit sugar but you could be missing out on protein, calcium and iron from foods you may be excluding such as bread, crackers, low-fat dairy, nuts and seeds.

Too much fruit can also have an effect on your digestive tract. A large amount of fruit in one sitting may cause diarrhoea, bloating and wind.

Fruit is high in sugar, and even though it’s fruit sugar, it is still sugar. Dried fruit and fruit juice are particularly concentrated sources of sugar and easy to overeat, meaning you could end up consuming a lot more kilojoules than you intended.

How much is too much?

There is no exact recommendation or guideline, but remember the suggestion of ‘5+ a day’ is based on two fruit and three vegetables. Having more than three or four servings of fruit each day may mean you don’t spend enough of your daily kilojoules on other foods which are equally important. For those with very large kilojoule requirements, such as very active individuals, more fruit may be appropriate.

  • Tip: Once you have reached three pieces/servings of fruit, change your snack to raw vegetables – veges are lower in sugar and add variety.

Great as a source of healthy fats, protein, vitamins and minerals including selenium, a powerful antioxidant. Brazil nuts (two to three a day) are commonly recommended as a way to get our daily dose of selenium.

What happens if you eat too much?

There is a fine line between the amount of selenium recommended for good health and the level which is considered unsafe or toxic. With Brazil nuts being so high in selenium, consuming too many can lead you into the toxic zone. Overdosing on selenium can cause brittleness and loss of hair and nails, tummy upsets, rashes, fatigue, irritability and nervous system abnormalities.

How much is too much?

The recommended dietary intake (RDI) of selenium for adults is 60 micrograms (mcg) each day for women and 70mcg each day for men. More than 400mcg each day is not recommended. One Brazil nut contains around 50mcg of selenium, so eight nuts would be the maximum recommended each day, without taking into consideration any other dietary sources of selenium. However, as Brazil nuts also contain high and variable amounts of barium and radium, it’s recommended we have no more than a few nuts each day.

  • Tip: Have two to three Brazil nuts a day – enough to keep healthy, but not enough to cause problems.

Vitamin C is a water-soluble vitamin. As one of its many functions, vitamin C is essential for the structure and maintenance of blood vessels, cartilage, muscle and bone. Because it cannot be stored in the body, it is important to include foods rich in vitamin C every day to get the amount needed for good health. Vitamin C is found naturally in vegetables and fruit.

What happens if you eat too much?

It is a common belief that large doses of vitamin C can prevent colds and make them go away more quickly. While maintaining a healthy level of vitamin C prior to getting a cold may reduce the severity and length of the cold, research shows that taking high doses of vitamin C once you have a cold has little benefit for the average person. While an upper limit has not been categorically determined, having too much vitamin C in a day can induce diarrhoea and has shown no consistent health advantages.

How much is too much?

The suggested daily intake of vitamin C for good health is 220mg for males and 190mg for females. There is no absolute upper limit but doses above 1000mg a day are more likely to cause bowel upsets.

  • Tip: Stick to vitamin C from foods rather than taking a high dose of supplements without prior medical advice.

This delicious, versatile oil is traditionally associated with Mediterranean cuisine. Olive oil is known for its heart protective properties, being rich in mono-unsaturated fats and packed with antioxidants.

What happens if you eat too much?

With TV chefs and many modern cookbooks suggesting using splashes and ‘glugs’ of olive oil, it can be easy to assume that the more, the better. While nothing catastrophic is likely to happen by using large amounts of oil, it is important to remember that oil is fat, just like butter, and very high in kilojoules. For those who are watching their weight, the haphazard splash or drizzle can add up to a whole lot of extra energy added to your day that you don’t even realise.

One tablespoon (15ml) of olive oil is around 500kJ. This is the same as one thick slice of bread, four grainy crackers or a glass of wine. This is the same for all varieties of olive oil, be they extra-virgin or ‘light’.

For an average adult, an evening meal might be about 2500kJ. So if you had, say, two tablespoons of oil in your dinner, you would have hardly any kilojoules left for food.

How much is too much?

Everyone is different, but in a healthy diet based on 8700kJ each day, it’s ideal to have around 45-80g fat a day. Stick to the lower end of this guideline if you are managing your weight.

  • Tip: Next time you add a splash or drizzle to your pan, pour it into a measuring spoon first and see how much you are using. You may be surprised.

The most widely consumed drink in the world with varieties including white, green and black.

What happens if you drink too much?

Tea by itself contains no kilojoules. Many varieties are packed with antioxidants and tea counts towards your daily fluid requirements. But while drinking endless cups of tea is highly unlikely to cause any major health dramas, it can have an impact on the way your body is able to absorb certain vitamins and minerals. Tea is high in tannins which have the ability to bind with iron, zinc and calcium and reduce the amount your body is able to absorb. While this may not have a significant impact on someone who includes plenty of these minerals, for a vegetarian or vegan or older people who are unable to absorb vitamins and minerals as well anyway, this may have an effect.

Although tea is lower in caffeine than coffee, it does still contain caffeine. An average cup contains anywhere between 10-50mg of caffeine. For most people 300-400mg a day is enough. Too much caffeine can cause irritability and disturb sleep. For pregnant women, keeping caffeine below 200mg a day is recommended.

How much is too much?

There is no set guideline for how much tea is too much but for most people, it is worth leaving a 30-minute gap between eating meals and drinking tea to maximise the body’s ability to absorb the minerals from food.

Dietary fibre is a type of carbohydrate which plays an important role in keeping things ‘moving’ in the gut as well as keeping the whole digestive system healthy. There are two types of fibre: soluble and insoluble. Both types of fibre have equally important but very different jobs. Fibre is found in whole grains, legumes, vegetables and fruit.

What happens if you eat too much?

Although fibre is undigested, it is fermented in the large intestine. Despite this fermentation being an important process, it does produce gas. If you rapidly increase the amount of fibre in your diet, it can result in you becoming very bloated and gassy and could cause diarrhoea or constipation. Also, if a very high fibre diet is started without increasing the amount of fluid you drink, things can get very uncomfortable in the bowel department.

For some people, having too much fibre can result in them feeling very full and not being able to eat a varied and balanced diet as they don’t have room. This is mainly a problem for young children who only have small stomachs and may feel full very quickly and not have room for the rest of their meals and snacks.

Fibre contains phytates which can bind with minerals such as magnesium, calcium, iron and zinc, meaning less of these are absorbed. This can be a problem for some vegetarians and vegans who may have very high fibre intakes and low amounts of these minerals.

How much is too much?

Don’t worry if you have no issues: most of us are getting less fibre than recommended, so getting too much is not a problem. But if you have runny poos or overfull kids, it may be worth looking into.

Women are advised to have at least 25g each day and men 30g. To work out the fibre requirement for a child, a rough guide is to add 10 to their age. For example, a six-year-old child needs 16g each day.

However, if you eat nothing but vegetables and fruit and do not have an overall balanced diet, or if you are a vegetarian or vegan, it may be important to consider the amount of fibre you are eating and possibly increase your intake of foods rich in iron, zinc, magnesium and calcium to be sure you are getting enough.