Fad diets don't work – at least not in the long term. Some reports suggest as much as 65% of people who lose weight by 'crash dieting' (a.k.a. extreme calorie reduction) will gain back ALL of that weight within 3 years.
During our time practising as registered nutritionists, we've encountered all manner of diets, fads, quick fixes and 'secrets' circulating in the health and wellness industry, all claiming to hold the key to weight loss success. As advocates for evidence-based nutrition, we're here to dispel the rumours and sort fact from fiction. Here's the real truth behind 7 of the most common dieting myths.
So often we hear people talking about 'cutting out bread' or 'banishing all starchy carbs from their house' in a bid to lose a few pounds. Just recently I heard someone say, “starchy carbs should be avoided as they have no nutritional benefit”! Sorry, what?!? Let me pick my jaw up off the floor. Carbohydrate-rich foods can be incredibly nutritious and should be included as part of a healthy balanced diet. In fact, did you know certain carbs could actually help aid weight loss? Yep, you heard me right. Wholemeal carbs which are rich in fibre can make us feel fuller for longer, helping us to eat less and so lose weight.
When it comes to carbs, it's all about the type we choose. Refined carbs found in white bread, white pasta, cakes, chocolate and sweets are not the best choices. These carbs are digested very quickly and broken down into sugars at a rapid rate, which means they cause our blood sugar levels to spike. We want to avoid this as it leads to a subsequent spike in insulin levels to help bring blood sugar levels back down again, which can cause a crash in blood sugar. Low blood sugar then results in cravings for more carbs, which creates a cycle of carb binges.
Choosing unrefined complex carbs doesn't result in this same cycle – foods like wholegrain bread, wholewheat pasta, brown rice, oats and quinoa are rich in fibre. Fibre slows down digestion as it bulks out our food and cannot be fully digested by our gut. This means it helps us to feel full for longer and also leads to a gradual release of energy, so we don't experience an immediate spike in blood sugar. Wholegrain carbs are also a source of B vitamins, iron and protein, so not only do they not cause us to gain weight – they're also highly nutritious!
The simple act of eating dinner late at night should not result in weight gain. Essentially, if you eat an appropriate number of calories across a 24-hour period, you should not put on weight, regardless of what time of day you eat.
That said, there is some research into circadian rhythms that suggests our digestive processes and metabolism are less 'switched on' later in the day, meaning calories don't get zapped up and utilised as they would if eaten earlier in the day. Also, eating later at night can sometimes lead to disrupted sleep, which can then affect our food choices the following day if we feel tired and lacking in energy.
However, it really all comes down to your total calorie consumption. Providing this is appropriate, you shouldn't gain weight just because you ate your dinner at 8pm. It's important to balance the social aspect of food with the healthiest approach. Many of us like to eat our largest meal with our family/partner/housemate at the end of the day – and to stop this for the sake of potentially losing a fraction more weight may not be worth it in the grand scheme of things.
There isn't any one food or diet that can put your body into 'detox'. We have a very clever organ called the liver that constantly detoxifies the body. Among its many essential responsibilities, the liver converts toxins in the body into waste products, cleanses the blood and produces bile for healthy digestion. You don't need to drink juices and soups for three days straight to do this!
While juice 'detox' diets are likely to dose you up on several vitamins, you'll probably consume way more than your body needs. Excess water-soluble vitamins are excreted out of the body, so you're paying a lot of money for some expensive wee! Juices are also very high in free sugars. When whole fruits and vegetables are blended up, the natural sugars within them are released, meaning they behave the same way as sugar added to food. Your body will experience a rapid spike in blood sugar following your juice, leading to an equally rapid 'crash' and inevitable feelings of hunger and irritability. If that wasn't enough, a juice-only diet means you'll be missing out on several fundamental nutrients, including protein, fibre and unsaturated fats. This golden nutrient trio is the key to feeling full and satisfied after a meal, not to mention the benefits for your heart, muscle, brain and gut health.
At best, liquid diets are only a very short-term solution to weight loss – long-term, it's not a safe nor sustainable approach. They fail to nourish the body with the nutrients it needs, and often foster an unhealthy relationship with food. While liquids are vital to hydrate the body, it's equally important not to cut out solid foods and entire food groups. The best way to achieve a calorie deficit is through a healthy diet containing a balance of food groups and plenty of whole, unprocessed foods.
While losing weight can be challenging, it need not be miserable! Some people may experience an element of hunger when they first switch to a lower calorie intake, but this should only be minor and shouldn't last for long. If you are finding you are feeling very hungry, it's most likely because you're not eating enough – and this is a definite no-no. Severely restricting your energy intake will lead to feelings of hunger, as this is our body's way of telling us we need to take in more food. Dropping to a very low intake (<1,200 calories per day) is not a sensible long term approach to weight loss, as our body will adapt to the low intake in a bid to preserve energy – subsequently making weight loss harder in the long run.
Following a moderate calorie reduction and making the best dietary choices means that you can lose weight without experiencing extreme hunger pangs. It's all about choosing nutrient-packed foods, particularly rich in protein and fibre – the two most filling nutrients – to help keep us feeling satisfied for longer and our blood sugar levels stable. Foods with a low energy density are a great choice too, as these provide bulk without adding loads of calories (think fruits, vegetables and soups). They have fewer calories per 100g than say chocolate or cheese, so you can eat a bigger volume of food for the same number of calories. This helps with feelings of fullness and satisfaction, to avoid feeling hungry.
Many fad diets will recommend cutting out certain foods such as all starchy carbs, takeaways, cakes, chocolate and wine, in a bid to make your diet as 'clean' as possible. This is really not necessary. While many of these foods ought to be treated as an occasional part of our diet, there is no need to cut them out completely. Having a little of what you fancy is necessary in order to stay on track with your eating plan. What we find is that cutting out all your favourite foods just leads to cravings, and eventually you throw in the towel and reach for a pile of chocolate biccies!
It's important to choose an approach that is sustainable rather than a quick fix. Unless you plan on never eating a piece of chocolate again, don't make that rule part of your diet. It's absolutely possible to lose weight while still enjoying the odd takeaway, glass of wine or bar of chocolate – it's just about striking the right balance. Taking a relaxed approach and including some treats makes losing weight successful and sustainable as it builds a long-term positive attitude towards food. Our motto is this – 80% of the time eat foods for nourishment, the other 20% eat foods for enjoyment. This is the best approach for long-term success!
A common misconception, especially amongst women, is that lifting weights will cause your muscles to bulk up, creating a larger appearance and a higher number on the scales. The requirements for creating such a physique are actually quite difficult. Bodybuilders and athletes need to be eating in a calorie surplus to see muscle growth, meaning they're eating well above the number of calories they're burning. For those of us eating at maintenance or in a calorie deficit, muscle growth in this way is far more challenging. In addition, the difference in hormone concentrations between men and women means it's even harder for women to look 'bulky'. Instead, lifting weights as a woman in a calorie deficit will help to create a toned appearance.
Growing a bit of muscle can actually help with overall fat loss. As muscle uses more calories than fat tissue, people with more muscle have a higher metabolic rate.
Similarly, increasing your protein intake could be a valuable strategy on your weight loss journey. Protein requires a longer digestive period than other nutrients, meaning it keeps us feeling fuller for longer. On top of this, the thermic effect of digesting protein is relatively high, meaning it needs more calories just to be digested.
A definitive recommendation for an upper limit on protein intake is still under discussion, but it's probably sensible to aim for no more than around 1.8-2g per kilogram of body weight per day as an absolute maximum. If we consume more protein than we need, our bodies will absorb the amount we require and then excrete the excess in our urine. Consuming too much protein long-term can increase the risk of kidney problems, and like all excess food, the energy from protein-rich foods can be stored as fat. A more sensible range for a higher protein diet would be 1.2-1.6g per kilogram of body weight per day.
There is also a limit to the amount of protein our bodies can absorb in one sitting. 25-35g appears to be the approximate range – any more seems to have little benefit and is likely to be excreted. So to get the most from protein in your food, spread your consumption across all of your meals in the day to improve the amount you absorb.
It might be tempting to severely restrict your calorie intake and to keep doing so in a bid to boost weight loss, but this just doesn't work long-term. Our bodies need energy and nutrients to function correctly – if we deny our bodies of this too much, then everything can start to slow down. Dropping your energy intake too low will not only be unpleasant, it will also not help your long-term success (read more here). We recommend an absolute minimum intake of 1,200 calories per day – 1,400 if you are someone who is relatively active.
There is some evidence that eating more and moving more is more conducive to weight maintenance than eating less and moving less – which is known as a higher 'energy flux'. For example, eating 1,600 calories and burning 400 calories through exercise may keep your metabolism higher than eating 1,200 calories and not doing any exercise. This supports the notion that our bodies function better when they are well-fuelled and nourished.
In summary, extreme approaches to weight loss are not the way to go. While you may experience weight loss initially, this tends to be unsustainable, and research shows many people will simply regain the weight – and some! It's not necessary to cut out foods or food groups, to experience severe hunger, or to time when you eat. The best approach is one you can stick to, which means making smaller healthy adjustments that you can sustain in the long run.
Nutritionists Emma Brown (ANutr), MSc Human Nutrition and Amy Wood (ANutr), MSci BSc Nutrition, are passionate about diet and how this impacts overall health. They support evidence-based advice around nutrition and aim to help everyone better understand how different nutrients affect the body and long-term health status.