6 healthy eating rules you probably follow – but nutritionists say you can ignore
- Melanie Leyshon
Published: October 13, 2026 at 11:28 AM
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Think you're eating healthily? Nutritionists reveal six common food rules that could be doing more harm than good – and what to do instead
From cutting out carbs to avoiding snacks, we're constantly bombarded with rules about what, when and how we should eat. But are these healthy eating habits actually doing us any good, or are we making life unnecessarily complicated? We asked nutrition experts which common food rules are worth following – and which ones you can happily forget.
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For more nutritionist advice, check out 6 foods you think are healthy – but nutritionists wouldn't eat every day.
Rule: You should avoid snacking throughout the day
Reality: Not all snacking is bad
Eating healthy portions of nuts, fruit and oatcakes can help maintain blood sugar levels throughout the day while providing essential nutrients many of us are lacking.
Snacks are also a good way to boost our fibre intake. Only four per cent of UK adults meet the recommended intake of 30g a day. "Fibre-rich snacks include nuts, seeds, wholegrain toast, oatcakes and roasted chickpeas," says dietitian Juliette Kellow. "Many of these are also useful sources of iron, another nutrient that many people in the UK, especially teenage girls and pre-menopausal women, are lacking."
Fruit and vegetables are excellent sources of potassium, which helps maintain healthy blood pressure. Yet more than a quarter of adults fail to get enough, says Kellow. "Combine fruit with plain yogurt, too, for a hit of iodine. Dairy products are rich in this nutrient, which supports our cognitive function – the way we think and process information. Yet 13 per cent of adults have very low intakes," she says.
Snacking can also help us stay alert. Kellow says that going for long periods without eating can cause blood glucose levels to drop, leaving us feeling tired, irritable and hungry, as well as making it harder to concentrate.
"If you’re likely to have a big gap between meals, then snacking on fibre-rich, carb-rich foods can help to combat this," she says. These foods break down slowly, providing a steady supply of glucose to fuel the body’s cells. ‘The brain needs a constant supply of energy and prefers glucose as its main fuel. This is why, when we’ve been without food for a long time, we can find it harder to concentrate, focus or think straight," says Kellow.
Also eating three meals a day isn’t suitable for everyone. For some people, having smaller meals and snacks works better with their lifestyle and eating habits. "It can also be really useful for people who have small appetites – whatever the cause, for example, illness or the use of GLP-1 medications," says Kellow.
For certain groups, healthy snacking can be particularly beneficial. "Growing children, teenagers, people working physical jobs or doing a lot of exercise can have higher energy requirements, so snacks can be a useful way to meet these needs," says Kellow. Check out our healthy snack recipes for more ideas.
Rule: You need to drink at least 1.2-1.6 litres of water a day
Reality: Water isn't the only key to hydration
Water is essential, but we don’t need to get all our fluids from plain H₂O, and our daily requirements vary from person to person.
"If you’re pregnant or breastfeeding, in a hot environment, physically active for long periods, ill or recovering from illness, or at risk of malnutrition, such as older people, you may need to increase your fluid intake," says registered nutritionist Gopi Chandratheva.
The Eatwell Guide recommends drinking six to eight glasses of fluid a day, with a glass defined here as 200ml. As well as water, this includes lower-fat milk and lower-sugar drinks such as tea and coffee.
Chandratheva says we shouldn’t become fixated on drinking a certain number of glasses of water. A better approach is to get fluids from a variety of sources.
"There’s a misconception that tea and coffee don’t count towards hydration because caffeine is a diuretic, but this effect is mild,’ she says. ‘So, for most people, tea and coffee can absolutely contribute to daily fluid intake."
We also get around 20-30 per cent of our water from food, particularly fruit and vegetables. Cucumber, tomatoes, courgettes, watermelon and strawberries are especially high in water, says Chandratheva. "They have the added benefit of providing fibre, vitamins, minerals and other plant compounds."
No single drink is superior for hydration, but variety can make it easier to meet our needs. Adding cucumber, mint, lemon or lime to still or sparkling water is another way to make it more appealing.
However, we need to be cautious about drinking fruit juices, squashes and fizzy drinks that contain added sugar. "Consuming too much can affect our health, particularly our teeth," says Chandratheva. She suggests switching to herbal teas instead. "Peppermint tea is known for its digestive effects, chamomile for its potential sleep benefits, and fruit herbal teas can be a good way to add natural sweetness," she says.
The best way to avoid dehydration is to sip fluids throughout the day and respond to your thirst. Check your urine colour when you go to the loo: pale yellow generally indicates good hydration, while dark yellow may be a sign you need to drink more. The key is to strike a balance – drinking enough without overdoing it, says Chandratheva.
Rule: Avoid certain fruits because they are high in sugar
Reality: The nutrients in fruit are valuable for health
It’s a misconception that some fruits should be avoided because they contain sugar, say the experts at the British Nutrition Foundation. While fruit does contain naturally occurring sugars, it also provides a wide range of important nutrients, including vitamins, minerals and dietary fibre, says Bridget Benelam, nutrition scientist at the British Nutrition Foundation.
"Fibre is particularly important because fruit can make a valuable contribution to increasing fibre consumption," she says.
It’s recommended that we limit ‘free sugars’ in the diet, but the sugars found in whole fruit are not considered free sugars because they remain within the cellular structure of the fruit, she says. In contrast, the sugars in fruit juices and smoothies are classified as free sugars, which is why it’s recommended to limit these to a combined total of no more than 150ml (a small glass) per day.
"Eating a variety of fruits can help maximise the range of nutrients in the diet, so rather than focusing on avoiding specific fruits, it’s more helpful to enjoy a colourful mix across the week," says Benelam. That’s because different fruits provide different combinations of vitamins, minerals and plant compounds, and variety can help support a balanced diet.
Fruit is also a convenient, portable snack that can be enjoyed throughout the day, she says. "Try adding berries to breakfast cereals or porridge, pairing apples or pears with cheese or nut butter for a snack, or incorporating a range of fruits into meals and desserts," says Benelam.
"From a health perspective, there is little evidence to support avoiding particular whole fruits simply because they contain more natural sugar than others. Only a third of UK adults are getting their five-a-day, so most people would benefit from increasing their overall fruit intake and variety," she says.
Rule: Always have breakfast
Reality: Don't eat if you're genuinely not hungry
"I wouldn’t necessarily say breakfast is the most important meal of the day, but I also wouldn’t dismiss it as unnecessary," says registered nutritionist Rob Hobson, author of The Low Appetite Cookbook.
"There are some really good reasons to eat breakfast, and research suggests it can help with appetite and fullness. Some studies have found that people compensate for skipping it by eating more at later meals, although that doesn’t necessarily mean they eat more calories across the whole day," he says.
Nutritionally, breakfast can also be a useful meal. Breakfast foods naturally lend themselves to some of the nutrients many of us could do with more of, particularly fibre, says Hobson. "Oats, wholegrain cereals and toast, fruit, nuts and seeds can all make a significant contribution, while yogurt, milk, eggs and fortified foods can provide protein and important vitamins and minerals," he says.
However, you don’t need to force yourself to eat first thing if you’re genuinely not hungry. "Breakfast is basically a morning meal and while some people may eat it at 7am when they get up, others naturally prefer to eat later and some people may skip breakfast altogether as part of intermittent fasting or time-restricted eating," he says. "Skipping breakfast may also reduce overall calorie intake for some people, although it isn’t a magic weight-loss strategy."
The important thing is to look at breakfast in the context of your whole diet, he says. "If you enjoy it, it’s a great opportunity to get some nutritious foods into your day. If you don’t feel like eating when you wake up, you can eat later when you are hungry and just make that first meal or snack something nutritious rather than feeling you have to eat breakfast simply because the clock says you should," says Hobson.
Even if you don’t eat breakfast straightaway, it’s still a good idea to have something to drink in the morning, he says. "Water, tea and coffee all count towards your fluid intake, so you can start hydrating even if you prefer to eat your first meal a little later." Check out more healthy breakfast ideas for inspiration.
Rule: Cut out white carbs as it’s better for your health
Reality: Carbohydrates are needed for energy
"The advice to never eat white carbs is unnecessarily restrictive," says Rhiannon Lambert, one of the UK’s leading nutritionists, founder of the Rhitrition Clinic and co-host of the The Wellness Scoop podcast. "UK government guidance recommends basing meals on starchy foods such as bread, rice, pasta and potatoes, choosing wholegrain or higher-fibre varieties where possible. These foods should make up just over a third of what we eat," she says.
During digestion, most starch is broken down into glucose, which enters the bloodstream and is used by our cells for energy. "Carbohydrate foods help meet the energy needs of everyday life, whether we’re working, exercising or fuelling children for a day at school. Some glucose is stored as glycogen in the liver and muscles, ready to be used when needed," says Lambert.
She cites good examples of carbs with extras: potatoes provide vitamin B6, vitamin C and potassium, as well as fibre, particularly when eaten with their skins; whilst white bread can contribute calcium, iron and the B vitamins thiamin and niacin because of the fortification requirements for most non-wholemeal wheat flour in the UK. Fortification is an established public health measure that helps support nutrient intake through foods people eat regularly.
However, fibre intake remains a concern. "Although we don’t need to avoid white carbohydrates, choosing wholegrain varieties where possible is a practical way to help close the fibre gap, alongside eating more beans, lentils, fruit, vegetables, nuts and seeds," says Lambert.
We also need to consider people’s circumstances, she says. "Availability, budget, cultural food traditions and taste preferences all influence what someone can realistically eat. Wholegrain options may not always be available, and some families prefer the taste or texture of white rice or pasta. A practical starting point is to consider what we can add to those meals to improve their nutritional value," she says.
Lambert suggests serving white pasta with lentils in a tomato sauce and vegetables. Rice could accompany beans, tofu or fish, alongside vegetables. A pizza made with a white flour base could have extra vegetable toppings and a side salad. "Depending on what we add, these meals can provide more fibre, protein and other nutrients while keeping foods people enjoy," she says. Browse our healthy carb recipes for more ideas.
Reducing carbohydrates can help some people lose weight, but it is not a requirement for weight loss or a healthier diet. "A 2022 Cochrane review of 61 randomised trials involving 6,925 adults with overweight or obesity issues found probably little or no difference in weight loss between lower-carbohydrate and balanced-carbohydrate weight loss diets over periods of up to two years," says Lambert. It also found probably little or no differences in several measured cardiovascular risk factors, including LDL cholesterol and diastolic blood pressure, she says.
Rule: Follow a long-term fasting diets for weight loss
Reality: Try fasting blocks instead
Intermittent fasting can lead to weight loss, but it can also be difficult to sustain. Instead of long-term fasting, nutritional therapist Amanda Hamilton suggests another approach.
"If I were going to incorporate fasting into my routine, rather than daily fasting I’d be more drawn to a five-day fasting-mimicking block once a season than intermittent fasting (IF) every day," she says.
"With intermittent fasting, the focus is typically on when you eat, restricting food to a narrower daily eating window. As an active woman in midlife, I’m not interested in constantly watching the clock to decide when I can eat – and the research on the benefits, particularly for active women in midlife, isn’t that compelling," she says.
Hamilton is more interested in the potential longevity benefits of fasting and finds a five-day block fits better into her life. "It gives me a clear beginning and end, and it also encourages me to reset some of my habits, slow down and be more intentional overall," she says.
"I’d never use packaged fasting products, supplements or pre-prepared kits. Nutritionally, those products don’t make much sense to me. If I’m going to eat a restricted diet for five days, I’d rather build it around menus that work for the season and actually taste good, too", she says.
"For me, it’s around 800 calories for four to five days, depending on how I’m feeling. It’s proportionate to TDEE (total daily energy expenditure)," she says. ‘It can’t be one-size-fits-all, or some people eat too little for the effect and others too much. No more than five days for anyone; the idea is never to lose lean muscle – that’s an own goal! I’m also a PT and compete in sports, so I’m more aware than most about this angle," she says.
Hamilton says what’s positive about fasting is that we see changes in markers associated with ageing and age-related disease. "Human trials have reported reductions in IGF-1, blood pressure and body fat, with improvements in some metabolic markers, particularly in people who started with higher risk factors," she says.
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Melanie Leyshon
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