Volume eating is a new name for an old concept: prioritising bulky, low-calorie foods over energy-dense fats to lose weight. What are the positives and pitfalls? Hatty Willmoth writes.

“Lose weight while eating more! Effortlessly eat more healthily, without feeling hungry! Achieve a calorie deficit without counting calories!”

Volume eating promises a lot. A quick Google search will tell you that it’s widely recommended by health professionals and dieticians as a tried and tested weight-loss strategy.

The reality may be much less exciting.

What is volume eating?

The crux of volume eating is the prioritisation of fibre and water content in foods, and the maligning of more energy-dense foods, such as those high in sugar or fat.

The thinking goes, weight management is decided by the energy we get from food. If we eat more energy/calories than we use, we gain weight; if we use more energy than we eat, we achieve a calorie deficit, and we lose weight.

A calorie is one unit of food energy, but different foods are more or less calorically dense. For instance, one small bite of doughnut (energy dense, high in sugar and fat) may contain the same quantity of calories as a whole bowl of salad leaves.

We can eat a greater volume of less energy-dense foods, such as salad leaves, without consuming many calories – so volume eating encourages eating these foods in large amounts.

The idea is that the stomach feels full of food while the body achieves a calorie deficit, so weight loss happens without going hungry.

In practice, volume eating involves eating a lot of roughage. Think veggies and salad – the more, the better – plenty of fruit and legumes, some carbohydrates, and a bit of lean protein.

Where does volume eating come from?

Volume eating is not new or radical. It has its roots in ‘volumetrics’: a more prescriptive version of the diet developed in 2000 by nutritional scientist Barbara Rolls.

As such, it’s not a million miles away from traditional 90s diet culture, with its calorie restriction, avoidance of fats, and preference for carbohydrates.

Today, it remains a popular method of weight loss, used by programmes such as Weight Watchers and Slimming World, and it has begun creeping onto social media with accounts such as @broccoli_mum bringing volume eating recipes to younger eyes.

As quite an old concept, it originates in old research. For instance, one study that is often cited in online articles dates all the way back to 1995, when groups of subjects were asked to rate foods as more or less filling.

They were given portions that were equal in terms of calories – so, very large portions of lettuce versus very small portions of cake.

Boiled potatoes scored the highest, as most filling per calorie, and croissants lowest, as least.

In general, researchers found that heavier foods were more filling, and the foods with the fewest calories per gram were judged to be less tasty.

Higher fat foods were also deemed less filling, but these are more energy dense so would have been served as smaller portions.

This isn’t a particularly impressive study; it’s based the opinions of a relatively small group of people, and it’s from ages ago.

But volume eating isn’t just a relic of the 90s; there have been subsequent studies to support it. A meta-analysis and review from 2016 confirmed that eating more energy dense foods is associated with obesity.

And Barbara Rolls, queen of volumetrics herself, has continued to publish research backing her own methods, such as a review from 2018 that concluded that strategically incorporating lower energy-density foods into a diet can “allow people to eat satisfying portions while improving dietary patterns”.

Really, it’s not rocket science. Swapping out sugary treats for more vegetables can mean enjoying bigger portions of food for fewer calories. So far, so straightforward.

Potential benefits of volume eating

For some people, volume eating might work well. Bulking out meals with kale and lettuce, and eating fruit for dessert, may mean it’s difficult to overeat, which could lead to better weight management for some people.

Nutritional therapist Kate Taylor says: “Fruit and vegetables are typically low calorie, and they are decent foods with plentiful phytonutrients, vitamins and minerals.”

Indeed, volume eating tends to be very plant-centric, which may mean benefitting from more nutrients in fruit and vegetables.

It may encourage eating a wider variety of plants too, plenty of experts are saying is key to good gut and whole-body health.

Volume eating is a high fibre eating pattern, which has benefits. Taylor explains: “Both soluble and insoluble fibre supports gut and digestive health and elimination (pooing)… and fibrous foods are typically satiating, which helps regular appetite management.”

There is evidence to suggest that eating more fibre may help people manage their weight by helping people feel full, even when restricting their calorie intake.

Volume eating may particularly facilitate weight loss in people who exhibit compulsive eating behaviours, for instance those who eat as a form of emotional regulation, to feel comforted or entertained, or as part of a food addiction.

A volume eating diet allows people to reduce the calories they’re consuming, without reducing the size of their plates, frequency of snacking, or quantities of mouthfuls of food – so they might be able to lose weight without nipping these habits in the bud.

Downsides and dangers of volume eating

The other side to that coin is that volume eating may encourage compulsive eating behaviours to continue, simply redirecting them towards different foods rather than tackling them head-on.

Volume eaters may continue to feel compelled to eat with a banquet mentality, but without the dopamine hit of sugary or ultra-processed foods – which could make it all too easy to slip right back into old habits if they become bored of so much roughage.

Volume eating may also take the joy out of food. Taylor says: “If you follow a strict dietary regime for too long, the way you judge a food going forward may change, and when a client comes off the volume eating regime, they may revert back to former less healthful eating habits, which may result in weight regain.

“Since the volume eating diet is also quite a dull style of eating, it may not be sustainable, and this may impact the client’s mental motivation going forward.”

It may not even be particularly filling. The point of volume eating is to physically fill the stomach, but satiety (feeling full) is more complicated than this.

“Appetite is hormonal,” says Taylor. “Ghrelin regulates hunger, signalling to the brain when you are feeling hungry, and leptin regulates satiety, signalling to the brain when you are feeling full.”

Research indicates that protein may be most effective at prompting these satiety signals – so volume eaters may feel stuffed but dissatisfied by their meals if they’re not getting enough protein.

And Taylor suggests that those who struggle with appetite regulation and weight management may have a hormonal problem, which volume eating would not address.

Not every gut wants more fibre

Plus, a diet full of fibre may not be suitable for everyone. Taylor says: “If a client is not used to a high-fibre diet, struggles with digestive issues, or has a health condition which makes their gut sensitive to high-fibre foods, this could lead to detrimental gut and excretion repercussions.”

In other words, too much fibre could lead to bloating, gas or diarrhoea in some people; more fibre isn’t always better.

Volume eating diets also prioritise carbohydrates over fats and to a lesser extent proteins, which may have the opposite of the desired effect.

Taylor says: “If the client is not able to exercise or move much, excess carbohydrate-derived sugars tend to be stored in fat cells, so if insufficient calories are being burned through exercise or movement, they may not achieve their desired weight loss goal.”

The problem with avoiding all calories equally

At its core, volume eating is a dietary pattern for weight loss, not optimum health, and as such it aims to reduce calorie intake first and foremost.

That gives the impression that calories are a negative attribute to food, to be avoided – whereas we need energy from food in order to survive and thrive.

Not everyone would benefit from reducing their calorie intake. Weight loss isn’t as simple as sustaining a calorie deficit, and weight isn’t a reliable determinant of health.

Taylor says: “Weight is multi-factorial and not always connected to food intake. For example, hormonal changes and stress can be environmental factors.

“Depending on the client’s lifestyle, they do need a certain amount of calories for the body and brain to function properly. If a client needs ample energy for a busy lifestyle, then they do need to appropriately fuel their body with ‘the right’ calories which do not necessarily come from ‘low calorie’ foods.”

She explains that ‘low calorie’ foods are not always healthy: “Many foods…claim to be low calorie but have lots of added artificial sweeteners which often have detrimental effects on gut health, which would be one of the priority areas to nurture with a weight loss client.

“Furthermore, there are different qualities of calories. I often compare an avocado with tons of nutrients, water and fibre, to a bag of ready salted crisps with virtually zero nutrient value but fewer calories than an avocado.”

Avoiding fats isn't a nutrition win

Avocado is one food that doesn’t fit into to a volume eating diet, because it’s high in fat and therefore more calorically dense than volume foods. This is a problem, according to Taylor.

She says: “Volume eating potentially restricts or eliminates highly nutrient-dense foods containing essential fatty acids (which are not synthesised by the body so must be gained through diet), such as avocado, eggs, extra virgin olive oil, oily fish, nuts and seeds.

“These confer many important macronutrients and micronutrients, alongside being high in fibre, as espoused by volume eating.

“Many natural and nutritious foods with a higher innate calorie count are also rich in vitamin D3 which is essential for supporting blood sugar balance, brain health, cellular health and mitochondrial energy generation, hormonal health, immune system function, regulating inflammation, musculoskeletal health, skin health, thyroid function… the list goes on.”

A poorly planned volume eating diet may also fail to accommodate an adequate protein intake, needed for muscle repair, immune function and more, and could in turn lead to deficiencies in nutrients associated with protein, such as vitamin B12.

Not even the plant nutrients are unaffected, because many vitamins rely on fats to be absorbed by the body.

Taylor says: “Vitamins A, D, E and K are fat soluble, so without sufficient essential fats in the diet, these vitamins acquired through the high proportion of fruit and vegetables consumed in volume eating may not be absorbed into the body as efficiently or in as great a quantity as would be considered optimal.”

Eat volume with a pinch of salt

Volume may be a useful way of thinking about food for some people. For those who wish to lose weight but struggle with appetite management, there are volume eating tricks that may prove beneficial.

For example, bulking out a meal with fibre and vegetables may lead to more satisfying eating, and beginning a meal with a soup or salad could aid blood sugar management.

However, it’s not recommended by nutritional therapists in general. Taylor says: “I would not be an advocate of volume eating as a dietary regime.”

Those who decide to prioritise volume in their eating habits may wish to exercise caution regarding their fat, protein and fibre intakes, and to try not to let it dictate their entire diet.

Taylor says: “Nutritional therapy is not necessarily about the quantity of calories a food contains, but rather about the quality of calories gained and bioavailable to the body from food.”

Losing weight with nutritional therapy

Instead of volume eating, nutritional therapy may offer an alternative route to addressing someone’s excess weight.

Taylor says she has no usual weight loss recommendations because every client is different and this area of health is highly individual.

However, she starts with “small, achievable modifications” as informed by a number of factors, such as ultra-processed food consumption, movement and exercise, time or stage of life, busyness, stress and any underlying health conditions.

Taylor also likes to recommend a Japanese philosophy of eating until 80% full, explaining: “This is fairly well evidenced as supporting weight management, as well as digestion, so this tends to be the philosophy I adopt with most of my clients.”

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