The volumetrics diet is a weight loss eating plan centered on the idea of feeling full while eating fewer calories. It’s typically not as well-known as other popular weight loss diets like keto and 5:2 – though research suggests that the volumetrics Diet may not only be more effective, but healthier too.
Here we’ll explore exactly what the volumetrics diet is – including its benefits, potential drawbacks, and the truth about whether or not it really works.
What is the volumetrics diet?
The volumetrics diet is an eating plan designed for weight loss. It’s based on the concept of filling up on low-calorie, nutrient-dense foods with a high-water content, while limiting intake of calorie-dense foods that release energy quickly.
By helping you feel fuller for longer, the volumetrics diet can naturally cut calorie intake and promote successful weight loss.
The volumetrics diet was developed by Dr. Barbara Rolls, PhD – a renowned nutritionist who has been studying obesity and hunger for over 20 years.
In her first book, Volumetrics: Feel Full on Fewer Calories, Dr. Rolls advises how to avoid high-foods, spot ‘calorie traps’ (food that appear healthy but have hidden calories), and discover lower-calorie foods that can leave you feeling full. Her second book, The Volumetrics Eating Plan, is a cookbook and lifestyle guide for how to follow the volumetrics diet in everyday life.
Unlike many other weight-loss diets, the aim of the volumetrics diet is to promote healthy eating habits that can be fostered as part of a long-term, sustainable lifestyle change rather than a short-term fix. It involves a more unstructured approach to eating, instead of restricting specific foods and drastically limiting calorie intake.
What does following the volumetrics diet involve?
Put simply, the volumetrics diet involves filling up on low-calorie, nutrient-dense foods while limiting high calorie foods foods.
As a guide, the diet separates food into four different categories based on their calorie density. Calorie density refers to the amount of calories in a given volume of food. Experts recommend getting the majority of your calorie intake from category one and two when following the volumetrics diet.
The categories are as follows…
- Category one (very low calorie density): calorie density of less than 0.6. Foods include non-starchy vegetables like broccoli, lettuce, cucumber; broth soups, and skimmed dairy products.
- Category two (low calorie density): calorie density of 0.6 to 1.5. Foods include starchier fruit and vegetables like bananas and sweet potatoes; low-fat meat products; legumes; and whole grains.
- Category three (medium calorie density): calorie density of 1.6 to 3.9. Foods include red meat, white bread, chips, and cheese like mozzarella.
- Category four (high calorie density): calorie density of 4.0 to 9.0. Foods include butter, chocolate, cooking oil, nuts, and pretzels.
Generally speaking, to work out the calorie density of a food you should divide the number of calories in a particular serving size by its weight in grams. This will give you a figure between 0 and 9. For example, there are 34 calories in 100g of broccoli, which gives it a calorie density of 0.34. Meanwhile, there are roughly 880 calories in 100g of sunflower oil, giving it a calorie density of 8.8.
However, while low-calorie-dense foods should make up the bulk of what you eat on the volumetrics diet, no foods are completely off-limits. The diet allows for flexibility to modify portions or adjust other meals in order to fit higher-calorie treats in if and when you want to.
The volumetrics diet generally recommends eating three meals a day, plus one snack. Below is a sample meal plan…
- Breakfast: Porridge oats with berries and almond milk
- Snack: Low-fat Greek yoghurt with apple and melon
- Lunch: Tuna with cucumber, avocado, and lettuce on whole grain bread
- Dinner: Chicken breast (without skin) with brown rice, grilled mushrooms, onions, and peppers
Lastly, the volumetrics diet also encourages people to exercise for at least 30-60 minutes each day. This can be as simple as taking yourself outside for a walk.
Is the volumetrics diet effective for weight loss?
There aren’t yet as many studies on the volumetrics diet as there are for other diet plans, but research has suggested that its main principles can aid healthy weight loss.
We’ll cover these two main principles below…
The volumetrics diet promotes controlled calorie intake
Eating foods with a low-calorie density has been found to be particularly effective for weight loss. This is because while these foods are low in calories, they still have substantial volume – meaning you can eat large servings without significantly increasing calorie intake.
This scientific review of over 3,000 people linked eating foods with a lower calorie density with greater weight loss; while another study found that eating more low-calorie, dense foods helped people to maintain their weight loss too. Similarly, this eight-year study of over 50,000 women linked a higher intake of calorie-dense foods with increased weight gain.
Choosing foods with a lower-calorie density is also thought to help curb cravings, regulate appetite, and promote portion control – all of which can encourage weight loss.
This study of women who were obese or had excess weight found that eating meals with a lower calorie density resulted in fewer cravings and greater feelings of fullness. Similarly, this study found that participants ate 56% more calories when served a large portion of food with a high calorie density, compared with a smaller portion of food with lower calorie density.
The volumetrics diet encourages regular exercise
As mentioned above, regular exercise (at least 30-60 minutes daily) is also encouraged on the volumetrics diet.
Staying active can be an effective way to promote healthy weight loss by increasing the number of calories you burn during the day.
What are some other benefits of the volumetrics diet?
Alongside it being an effective diet plan for healthy weight loss, there are a number of other potential benefits to the volumetrics diet too.
We’ll outline some of these below…
The volumetrics diet may improve overall diet quality
Prioritising your intake of low-calorie-dense foods like fruit, vegetables, and whole grains isn’t only effective for weight loss, but can boost your health too.
This is because high volume, low-calorie foods tend to have more water, fibre, and nutrients, and are low infat – while high-calorie dense foods contain less water, fibre, and nutrients, but are high in fat. Therefore, following the volumetrics diet guidelines may also help to up your intake of essential vitamins and minerals.
As a result, research has linked diets with a low-calorie density with improved overall diet quality.
The volumetrics diet limits intake of processed foods
While no foods are completely off limits on the volumetrics diet, because the majority of processed foods have a high-calorie density, they’re not consumed in large amounts.
Not only do processed foods typically lack in essential nutrients like protein, fibre, vitamins, and minerals, their high calorie, fat, sugar, and salt content links them with a greater risk of health conditions like heart disease, diabetes, and cancer.
The volumetrics diet is accessible to various dietary requirements
Because there aren’t any extreme restrictions to the volumetrics diet, whether you’re vegan, kosher, or diagnosed with a medical condition like celiac disease, you can eat according to your needs.
The volumetrics diet is flexible and sustainable long-term
Unlike many other weight loss eating plans, the volumetrics diet offers a flexible and healthy approach that makes it a sustainable, long-term lifestyle change rather than a ‘quick fix’ diet.
There are a few reasons for this; the first being that the volumetrics diet is centered around the goal of eating to feel full and satisfied – which contrasts with many other diets that set extreme calorie deficits, leaving you feeling hungry and more likely to quit.
There’s also an element of flexibility to the volumetrics diet which means no foods are entirely off limits. This allows people to honour their cravings from time to time and allow the diet to fit in around their lifestyle – for example, having a slice of cake on their birthday. Often, this lack of restriction is not only healthier but can lead to better results too because you’re more likely to stick with it long-term.
For this reason, some experts have described the volumetric diet as a ‘come for the weight loss, stay for the health benefits’ kind of eating plan.
What are the disadvantages of the volumetrics diet?
While there are a number of positives to the volumetrics diet, there are also a few drawbacks to be aware of too.
This includes the fact that…
The volumetrics diet limits intake of healthy fats
One of the biggest downfalls of the volumetrics diet is that it doesn’t distinguish between healthy and unhealthy fats.
This means that alongside cookies, cakes, and butter (which contain unhealthy fats), healthy fats found in foods like nuts, seeds, avocado, and oils are also limited.
Healthy fats like omega-3s form an essential part of any healthy diet and offer a number of important health benefits. This includes their ability to reduce inflammation, boost brain health, and lower the risk of chronic health conditions such as heart disease and diabetes.
Unfortunately, this aspect of the volumetrics diet also pits it against a number of other healthy and reputable eating patterns such as the Mediterranean diet, which encourage the consumption of healthy fats.
The volumetrics diet can be time-consuming and expensive
Due to its emphasis on fresh fruit and vegetables over processed foods, grocery shopping and meal-preparation for the volumetrics diet can be expensive and time-consuming.
This can make it difficult to follow for people who have tight schedules or budgets, because the majority of meals and snacks will need to be brought fresh and prepared at home.
Who is the volumetrics diet not suitable for?
There are a number of benefits to the volumetrics diet. That being said, it might not be suitable for everyone.
For example, if you struggle with gastrointestinal issues such as irritable bowel syndrome (IBS), it’s possible that the volumetrics diet may exacerbate your symptoms. For this reason, you may find diets such as the low-FODMAP diet more suitable. However, it’s important to talk to your doctor first before starting any new eating plan.
The volumetrics diet is also not advised for athletes or other highly-active people because it’s unlikely to provide them with enough energy. Similarly, if you’re currently struggling, or have struggled with an eating disorder in the past, it’s generally best to avoid the volumetrics diet (or any other weight loss diet) as this can contribute towards an unhealthy, restrictive mindset.
Final thoughts…
There are a number of benefits to the volumetrics diet that can make it an effective weight loss tool and sustainable, healthy long-term eating plan.
For further reading, head over to the diet and nutrition section of our website. Here you’ll find various other diet guides and a range of tips for healthy living.