20 Reasons Why Context Matters with Nutrition

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Every weekday during the month of September I shared an example of why ‘context matters’ when it comes to nutrition on my instagram, twitter and facebook.

I wanted to highlight how ‘one size fits all’ nutrition advice rarely works in the long-term (with the exception of public health guidelines which are evidence-based and designed to be used as a general guide for most people to follow).

This had been on my mind a lot lately, as nutrition messages are often presented in such a ‘black and white’ way, but there are so many nuances and different things to consider, so no food is simply ‘good or bad’. This is why when I get asked a question about nutrition, my answer usually starts with “well it depends on…”.

These examples obviously don’t cover every possible nutritional context, but they highlight how the same food can be viewed in 2 very different ways depending on the situation.

And because context matters so much when it comes to nutrition, it is often important to get individual dietary advice from a health professional (like a Dietitian or Registered Nutritionist) if you have specific dietary concerns.

Let’s take a look at some #ContextMatters examples:

1. Jelly Babies

Jelly babies are high in sugar, and most people in Western countries already eat more sugar than is recommended 🍬

BUT they can also be part of a life-saving treatment for a person with Diabetes who has a hypo (a very low blood sugar level)! – although a more severe hypo may need to be treated with glucagon 👩‍⚕️

They can also be a handy way provide energy during endurance exercise like running a marathon 🏃

2. Kale

On the one hand this is a nutritious vegetable, and most of us would benefit from eating more veggies every day 🌱

BUT eating too much kale can reduce the effect of a blood-thinning medication called Warfarin, and a really high intake can also be bad for our thyroid (e.g. if having multiple glasses of kale juice per day!) 👩‍⚕️

So even a vegetable like kale can’t simply be classified as ‘good or bad’!

For most people including some kale in your diet (if you like it) is a healthy thing to do, as long as you don’t go OTT with it!

3. Wholewheat Food

Foods like wholegrain bread, weetabix and brown pasta are a great source of fibre.

Getting enough is good for bowel and heart health, and in the UK & Ireland most of us don’t reach the recommended 30g of fibre per pay 💩

But as these contain gluten they are harmful for people with coeliac disease, and they also contain fructans which can cause bloating and bowel problems for some people with IBS 👩‍⚕️

So for most people eating more wholegrains is a really healthy thing to do, but as always there can be exceptions to this.

4. The Keto Diet

This is a high fat, very low carbohydrate diet which:

  • Excludes sugary food or drinks, beans, pulses, wholegrains or starchy carbohydrates (food like potatoes, pasta and rice)
  • Limits higher carb fruit and vegetables
  • Is usually high in: meat, fish, chicken, eggs, butter, cheese, cream and oils

This diet is used as a medical treatment (under the supervision of a doctor and dietitian) for some people who have specific metabolic disorders, or for some children with epilepsy which can’t be managed with medication  💊

But this diet is very restrictive and unbalanced as it cuts out or limits many nutritious foods (carbs – the main source of fuel for our body, wholegrains, fruit, vegetables, pulses etc) – so without a specific medical reason, it usually isn’t a good idea to follow this diet 🙅‍♀️

And although people tend to lose weight in the short-term from low carb diets like this, the body of evidence shows us that low carb diets aren’t the best choice for long-term health 📊

There is also no strong evidence in humans that the keto diet promotes general health or cures specific diseases.

For more information on the keto diet, check out this article I wrote for The Food Medic’s Educational Hub.

5. Orange Juice

150ml of orange juice (which is one small glass) counts as one of our 5-a-day and is a great source of vitamin C 🍊

BUT drinking orange juice in large amounts (i.e. much more than 150ml) provides a lot of sugar, because the fibre from the orange has mainly been removed which means that orange juice contains ‘free sugars’.

So too much is bad for our teeth and it can sometimes cause gut problems for some people – like wind, bloating and diarrhoea 💩

Because of this high sugar content, it is also advised to dilute fresh juice with 1 part juice to 10 parts water for young children, and it is best to have this with a meal.

So this can be a good addition to our diet, but it is best for adults to try and stick to one 150ml glass per day, and for young children to have this diluted with water.

6. Nuts

Nuts are a great source of protein, healthy fats and fibre, and also contain: vitamin E, B-vitamins and minerals like: selenium, iron, calcium, zinc, potassium, magnesium, manganese and copper.

Some studies have also found that having a 30g (small handful) of nuts per day may also reduce the risk of heart disease ❤️

But for those who have a nut allergy, these can cause unpleasant side-effects like vomiting, diarrhoea, swelling, itchiness, difficulty breathing or swallowing and in severe cases this can cause anaphylaxis which can be lethal 👩‍⚕️

So for those without a nut allergy, having roughly a small handful of unsalted nuts per day is usually a healthy addition to a balanced diet.

7. Grapefruit

Half of a grapefruit counts as 1 of our 5-a-Day, it is a great source of: vitamin C, and also provides vitamin A (in the precursor form of beta-carotene) and fibre.

But grapefruit – and grapefruit juice in particular – certain statins (cholesterol-lowering medication). It can increase the level of Simvastatin in the blood which increases the risk of side-effects, and a large intake can interfere with Atorvastatin as well 👩‍⚕️

Grapefruit also interacts with a number of other medications including: calcium channel blockers, immunosuppressants and warfarin (for more information see  the NHS website) – if in doubt it is best to speak to your doctor about this if you include grapefruit in your diet 💊

But if you aren’t on these medications and you like grapefruit, then it can be a good food to include in your diet

8. Soya Milk

This is one of the better plant-based milks in terms of nutrition (as long as it is fortified with calcium).

This because soya milk contains more protein than nut, coconut and oat milks and importantly it contains all of the essential amino acids in good amounts. Some types of soya milk now have iodine added too, which is important as dairy is the main source of iodine in the UK 🥛

And there is also quite good evidence that a regular intake of soya is good for our heart and may reduce the severity of menopausal hot flushes for some women.

But soya can be harmful to those who have a soya allergy and can reduce the absorption of thyroid medication 💊

So overall soya milk is usually a healthy choice, except for those who have the specific medical conditions mentioned above.

But soya milk isn’t necessarily healthier than cow’s milk, and if you don’t include dairy products in your diet it is important to make sure that the soya milk you buy is fortified with calcium and that you are getting enough iodine in your diet (from fish, seaweed, fortified products etc).

9. Vitamin & Mineral Supplements

Supplements can be used to correct nutritional deficiencies for those with certain medical conditions or a limited diet.

It is also really important for women to take folic acid supplements when they are planning a pregnancy and for the 1st trimester of pregnancy in order to reduce the risk of neural tube defects (NTDs) like spina bifida for their baby 🤰

In the UK it is advised that everybody over the age of 1 should consider taking a vitamin D supplement, especially from October to March when there isn’t much sunshine ☀️

The UK government also recommends that children between 6 months and 5 years old take a daily vitamin C and vitamin A supplement (as well as vitamin D)👶

Babies from birth to 1 yearshould have a daily 8.5- 10 microgram vitamin D supplement – unless they are formula fed and having more than 500ml of infant formula 🍼

But for most people, vitamin and mineral supplements are unnecessary as it is better to get these nutrients from a balanced diet (with the exception of vitamin D).

It is also important not to take high doses of supplements or multiple supplements which contain the same vitamins or minerals.

For example a high quality study (Cochrane review) from 2012 found that most supplements didn’t reduce the risk of diseases. In fact taking vitamin E, and high doses of vitamin A was associated with a higher risk of early death 📈

Overall, supplements can be useful in some cases, but don’t go supple-MENTAL!

For more information on this check out the British Dietetic Association (BDA) food factsheet about supplements.

10. Sports Drinks

These can be useful for fuel and hydration for some people who do moderate to high intensity exercise for longer than 1 hour 🏃‍♂️

Otherwise sports drinks can provide unnecessary sugar, salt and calories – water is the best drink for most people who exercise for less than 1 hour 💦

And for those who do exercise for longer periods you can also make your own sports drink by:

  • Mixing water with full-sugar squash if exercising for more than 1 hour
  • Add a small amount of salt to this if exercising for more than 2 hours or in hot weather
  • Or have a milky drink after exercising as this contains fluid, protein, carbohydrate and sodium

For more information and directions on making these drinks check out this post by Anita Bean (Registered Nutritionist).

11. Coffee

This caffeine in coffee provides a much appreciated energy boost and can improve alertness for many people.

Coffee is also high in antioxidants (like polyphenols and hydrocinnamic acids) and some studies have found that having 3-4 cups a day might reduce the risk of diseases like: heart disease, cancer, type 2 diabetes and non-alcoholic fatty liver disease (and the same potential benefit has been seen for decaf coffee) 📊

But some people don’t tolerate the caffeine in coffee well, so this can cause headaches, sleep disruption, heart palpitations and anxiety. Different people also metabolise caffeine differently, and you can also build up a tolerance to this.

So some people can consume quite a lot of coffee without getting these side effects, but others (like me!) experience this from a small amounts of coffee 😰

For those who struggle to sleep, it is recommended to have your last caffeinated drink 12 hours before you go to bed 😴

Coffee is also high in tannins, which can reduce our iron absorption if consumed within about 30 minutes of a meal 🥩

And coffee can irritate the gut for some people too (again people often have different tolerance levels to this).

So for most people having 3-4 cups of brewed or instant coffee per day is within the recommended daily caffeine limit, and may offer extra health benefits.

But the timing of this may effect sleep, and if you get jittery and anxious from coffee it may be best to reduce your intake or switch to decaf.

12. Onions & Garlic

These can provide a lovely bit of flavour to a meal, as well as a little bit of fibre, and some vitamins and minerals e.g. garlic is a good source of vitamin C, vitamin B6 and magnesium. But of course it depends on how much garlic we eat, as 1 clove in a big pot of pasta sauce isn’t going to make much difference to the nutritional content!

These foods also contain prebiotics which feeds the good bacteria in our gut 💩

But they can trigger bloating, abdominal pain and bowel problems for some people with IBS because they are high FODMAP foods (types of carbohydrates that are poorly absorbed in our small intestine) 😰

So these are usually a beneficial additional to the diet, except for those who have IBS and are sensitive to onion and garlic.

And by the way, there is no good evidence that eating garlic prevents or cures a cold! 🤒

13. Protein Shakes

These can be a convenient way to meet the increased protein requirements for muscle recovery after exercise – especially for strength and endurance athletes 🏋️‍♂️

If you do use protein supplement, make sure that these are good quality and batch-tested as some protein supplements sold online have been found to contain harmful and illegal substances. You can also get individual advice from a Sports Nutritionist or Dietitian about whether this would be useful for you, and what type to use.

But these aren’t always necessary, because most people already have a high amount of protein in their diet, and the extra protein needed for muscle recovery can be met by including ‘complete protein’ sources in the diet – like milk, soya milk, yoghurt and eggs 🥛

The BDA advise that when energy requirements are met, a balanced diet should provide enough protein to meet the extra protein intake needed for exercise recovery.

For more information, check out my previous post about the pros and cons of protein shakes.

14. Beef Liver

This high iron food can be useful for people who suffer with anaemia to include in their diet as 3-4 slices contain the daily recommended iron intake for adults (11.3mg for men and 14.3mg for women) 💪

But because liver is very high in vitamin A, it needs to be avoided by pregnant women as this can harm a developing baby 👶

The high iron content of liver could also be harmful for a person with a rare genetic disorder called haemochromatosis – where the body stores too much iron.

So this is a good example of how the same food can either be helpful or harmful, in the context of different medical conditions and different life-stages.

15. Gluten-free Diets

This is a vital treatment for those who have coeliac disease.

A gluten-free diet may also help to relieve gut issues for those with non-coeliac gluten sensitivity – but this is a newly defined and poorly understood condition 💩

But for most people this is an unnecessary restriction as it is estimated that only 1% of the population have coeliac disease and 1-6% have non-coeliac gluten sensitivity.

Studies have also found that gluten-free diets are usually lower in fibre and higher in sugar than a gluten-containing diet, as well as being more expensive to follow 💸

So except for those with a medical reason to avoid gluten, there is no need for most people to follow this diet

16. A Medium McDonald’s Milkshake

A medium McDonalds Milkshake (in the UK & Ireland) contains about 380 calories and 47 – 59g of sugar (which is roughly double the daily recommended intake for an adult).

But because some of this sugar is the lactose which is naturally found in milk rather than added sugar, there is likely to be at least 7 – 10 tsp of added sugar per medium shake, and most people already consume more than the recommended intake of sugar per day 🍭

But on the other hand, having a milkshake like this can be a tasty way of getting a good intake of calories and 10g of protein for somebody who has a poor appetite or is trying to gain weight 💪

As this contains milk it will also provide some calcium, iodine, B-vitamins, phosphorus and potassium 🥛

So a drink like this is actually very nourishing, especially for somebody with a poor nutritional intake.

We don’t always think that malnutrition is a big problem in Western countries but in the UK for example, 1 in 10 people over the age of 65 is malnourished or at risk of this, and malnutrition costs the NHS an estimated £19.6 billion per year. You can find more information about malnutrition in the UK from the BAPEN website.

17. Aspartame

This artificial sweetener is used in many products as a way of providing sweetness while keeping calorie content down and being less damaging to our teeth than sugar 👄

Aspartame also has a bad reputation as some say that it causes cancer – but this has been rigorously tested and is deemed safe to consume in our diet up to 40 mg/kg of our body weight (which is way more than most people would consume e.g. this would be 14 – 15 cans of diet coke based on my weight!).

The initial fear of aspartame came form studies in the 80s and 90s which was carried out in rats. But we now have strong human evidence that aspartame does not increase cancer risk when consumed within the recommended limit mentioned above 📉

There is also an approved health claim that aspartame (along with other types of sweeteners) is good for our teeth and stabilising blood sugars after a meal.

But aspartame is dangerous for those who have a rare condition called Phenylketonuria (PKU) to consume because it contains phenylalanine which can build up to a dangerous level due to a missing enzyme (i.e. this cannot be properly metabolised).

Artificial sweeteners like this are not recommended for babies and children under 3 because of a lack of testing in this group, their low weight and because young children need an energy dense diet to support their growth and development 🧒

Sweeteners such as aspartame may also alter gut bacteria in a harmful way – but most of the research on this has been done in animals so more research is needed to investigate this 🔬

So aspartame and other sweeteners can be used as part of a balanced diet, but as always it depends on the context!

18. Vegan Diets

Vegan diets are often high in fruit, veg, pulses, nuts, seeds and wholegrains. This may be part of the reason that this diet is often associated with a lower risk of chronic diseases like heart disease and cancer (although vegans are more likely to be young, educated, active, non-smokers which also effects the risk of these diseases).

The arguments about animal welfare and sustainable eating for the environment associated with veganism are also strong 🌍

But as this diet cuts out food groups it increased the risk of nutritional deficiencies if close attention isn’t paid to diet composition – e.g. low calcium, iron, iodine and vitamin B12 intake. This can be particularly dangerous for vulnerable groups like babies and young children.

You also don’t need to go fully vegan to get a lot of the benefits of this diet, as much of this can be achieved by eating more fruit, vegetables, wholegrains etc or having a ‘flexitarian’ type approach 🥦

Of course vegan diets aren’t automatically healthy, as it depends on the overall dietary intake 🍟

There is also a link between vegan/vegetarian diets and disordered eating. However, it isn’t clear whether these diets increase the risk of an eating disorder, or are used as a way to hide the symptoms of an existing eating disorder.

So the healthiness of a vegan diet depends on the individual person and their individual dietary intake.

For advice on how to achieve a balanced vegan diet you can seek support from a Registered Dietitian.

I have also included more info in my blog posts: Nutritional Advice for Vegans and Vegetarians, and What you Need to Know about Vegetarian Meat Alternatives.

19. Bananas

Bananas provide fibre, carbs, vitamins and minerals (like: potassium, magnesium, vitamin C and vitamin B6) – I have also heard them named as the most popular fruit in the world! 🌍

The potassium found in a bananas is usually good for us, as it can help to keep our heartbeat regular and our muscles healthy.

But some people who have kidney disease will be advised by their doctor not to include too much potassium in their diet, as potassium levels in the blood can get dangerously high in some cases which can cause an irregular heartbeat or increase the risk of a heart attack.

Remember that one small to medium banana or 1/2 a large banana counts as one portion of our 5-a-day, 🍌

A common myth about bananas is that they are ‘fattening’ – this isn’t true. Bananas do contain more calories than some other types of fruit, but a medium banana still only contains ~100 calories. Of course eating large amounts of anything will increase our calorie intake, which can increase the likelihood of weight gain, but bananas are unlikely to be one of the highest sources of calories in our diet! ⚖️

I also hear people say that bananas should be avoided because they are high in sugar – this also isn’t true as the sugar found in bananas is naturally occurring and is bound with other nutrients and fibre which slows our absorption of it. So the sugar found in bananas doesn’t count towards the recommended 30g per day free sugar limit for adults.

If you like bananas, then having one per day is a healthy addition to a balanced diet – unless you have been advised to reduce your intake of potassium by your doctor.

20. A Donut (or any food!)

OK so my last #ContextMatters post isn’t really about donuts, it’s about ANY type of food! 🍩

Because the context of what we each like to eat, and what we are in the mood for matters too, as eating should be a satisfying and joyful experience.

I chose a donut to make this point because this is often seen as a ‘bad’ or ‘naughty’ food – but as I’ve been going on about for the past month no food is simply ‘good or bad’ in all contexts! 😈

It obviously wouldn’t be great for us if we ate massive amounts of donuts on a regular basis, but it also doesn’t promote a healthy relationship with food if we have rigid food rules in place, or if we think of a food we enjoy as completely ‘off limits’ 🙅‍♀️

So flexibility and allowing ourselves to savour every mouthful of a food we enjoy is important.

For more info on this topic, Laura Thomas (PhD, RNutr) shares great content about intuitive eating on her social media pages, and in her podcast ‘Don’t Salt My Game’.


So I think I’ve well and truly made my point that #ContextMatters! 😜


*Remember, no information shared on this website is intended as individual advice. This is intended for general information. Always speak to your doctor or another relevant health care professional for individual advice about related to your health. For more information see my disclosure policy


Maeve has been consulting on The Food Medic Educational Hub for 12 months now and has been a huge asset to the team. Her ability to translate some very nuanced topics in nutrition into easy-to-follow, informative articles and infographics is really admirable.

Dr Hazel Wallace

Founder of The Food Medic

Maeve is incredibly talented at sharing scientific information in an easy to understand way. The content she shares with us is always really interesting, clear, and of very high quality. She’s one of our favourite writers to work with!

Aisling Moran

Senior UX Writer at Thriva Health

Maeve has written extensively for NHD magazine over the last few years, producing a wealth of dietetic and nutritional articles. Always evidence based and factual, Maeve creates material that is relevant and very readable. She provides high quality work with a professional and friendly approach. Maeve is a beacon of high quality knowledge and work within the nutrition writing community; and someone NHD magazine is proud to work with.

Emma Coates

Editor of Network Health Digest

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