When people think of dieting, a fairly miserable line-up of small portions and boring salads might spring to mind. The Volumetrics Diet takes a different approach, encouraging you to eat larger amounts of certain foods with the aim of keeping you fuller for longer.

Eating more might sound like the opposite of what you need to do to lose weight. But the principle behind the Volumetrics Diet is relatively straightforward: fill your plate with foods that provide plenty of volume for relatively few calories and you may find it easier to maintain the calorie deficit required for weight loss.

The approach can be particularly useful for men who want to lose weight without constantly feeling as though they’re eating tiny portions, according to Joey Gochnour, RDN, NASM-CPT, registered dietitian nutritionist at Nutrition and Fitness Professional.

Here’s what you need to know.

What Is the Volumetrics Diet?

The Volumetrics Diet was developed by Barbara Rolls, PhD, a nutrition researcher at Penn State University. Rolls later outlined the approach in her book, The Ultimate Volumetrics Diet.

The basic idea is to keep you feeling full while reducing your overall calorie intake. Most weight-loss diets ultimately rely on maintaining a calorie deficit, but the Volumetrics approach places particular emphasis on choosing foods that allow you to eat larger portions for fewer calories.

‘If you fill up on low-calorie, healthy foods, you won’t feel as hungry as you might on most other weight-loss diets,’ says Sonya Angelone, RD, PhD, dietitian and former spokeswoman for the Academy of Nutrition and Dietetics.

Regular exercise is also encouraged alongside the eating plan.

How Does the Volumetrics Diet Work?

The diet encourages you to eat more foods with a high water and fibre content, including soups, stews, fruit and vegetables. These foods physically take up more room on your plate – and in your stomach – without necessarily delivering a large number of calories.

‘This diet is based on the calories per gram of food or energy density,’ Angelone explains. ‘Foods that contain more water and fibre will have a greater volume with fewer calories so that you can feel fuller on the larger volume while naturally eating fewer calories.’

The diet leans heavily on fruit, vegetables, lean proteins, pulses, whole grains and other fibre-rich foods. Alongside potentially making a calorie deficit easier to maintain, many of these foods provide protein, fibre, vitamins and minerals that support wider health.

What Can You Eat on the Volumetrics Diet?

Technically, no food is completely off-limits. Instead, the Volumetrics Diet divides foods into categories according to their calorie density – calculated by dividing the number of calories in a serving by its weight in grams.

You’re encouraged to eat more foods with a low calorie density and smaller portions of foods with a higher calorie density.

• Category one: These foods have a calorie density below 0.6 and should make up a large proportion of your diet. They tend to have a high water content and include foods such as berries, melon, broccoli, beetroot, carrots, fat-free yoghurt and skimmed milk. Broth-based soups also fall into this category.
• Category two: Foods in this category have a calorie density of 0.7 to 1.5 and can be eaten in moderate amounts. Examples include skinless chicken, lean beef, lentils, chickpeas, potatoes, squash, brown rice and quinoa.
• Category three: These foods have a calorie density of 1.6 to 3.9 and are generally eaten in smaller amounts. They include fattier cuts of meat and fish, cheese, whole milk, pasta and white bread.
• Category four: Foods in this category have a calorie density of four to nine and are eaten more sparingly. Examples include nuts and seeds, oils, fast food and sweets.

What Does a Day on the Volumetrics Diet Look Like?

Here’s an example of a full day’s eating on the Volumetrics Diet, according to nutrition experts.

Breakfast

Vegetable omelette with a side of fresh berries or melon.

Lunch

A large rocket salad with sliced cucumber, grated carrots, cherry tomatoes, chickpeas, grilled chicken and around half a cup of cooled roasted potatoes with a vinegar-based dressing, served alongside a bowl of vegetable soup.

Snack

Plain fat-free Greek yoghurt with berries and watermelon.

Dinner

Baked cod with brown rice, roasted vegetables and fresh fruit such as melon, berries or grapes.

What Are the Pros and Cons of the Volumetrics Diet?

One of the biggest advantages is the lack of outright food restrictions. The approach can also encourage eating habits that are more realistic to maintain over the long term than highly restrictive crash diets.

‘This diet is intended to make permanent changes to your food choices, not just while you are losing weight,’ Angelone says.

Gochnour also points to the evidence supporting the basic principles behind the approach.

‘Eating high water, high fiber foods is evidence-based weight loss and fullness guidance, not fad,’ he says.

There is some research specifically examining the diet, too. A small study involving people with overweight or obesity found that those following a Volumetrics Diet achieved similar weight-loss results to participants following a time-restricted eating plan. Both groups experienced significant reductions in bodyweight after 12 weeks.

There are drawbacks, however. One is that categorising foods purely according to calorie density can make nutritionally valuable higher-fat foods appear less desirable. Gochnour stresses that a balanced diet should still include sources of healthy fats.

Angelone also points out that calorie density doesn’t necessarily tell you about the overall nutritional quality of a food. Nuts and seeds, for example, sit in the highest-calorie category despite providing protein, fibre, vitamins, minerals and unsaturated fats.

Is the Volumetrics Diet Worth Trying?

The Volumetrics Diet could be useful for men looking to lose weight while learning more about portion sizes and the types of foods that can keep them satisfied.

Angelone says the approach can be particularly straightforward because it doesn’t require complicated calculations at every meal. A simple way to think about it is to fill a substantial portion of your plate with non-starchy vegetables, alongside a source of lean protein and a portion of whole grains or starchy vegetables.

There are some people for whom the approach may be less suitable. Gochnour points out that athletes with particularly high energy requirements may struggle to consume enough calories if they’re filling up predominantly on high-volume, low-calorie foods. Large amounts of fibre and high-volume foods may also prove uncomfortable for some people with digestive issues.

Ultimately, the Volumetrics Diet isn’t a magic weight-loss hack. Its potential benefit is much simpler: by prioritising filling foods with a relatively low calorie density, it may make eating fewer calories feel considerably less like you’re eating less food.

As Angelone puts it: ‘This is great for someone who is ready to change their eating habits and isn’t looking for a quick fix.’

Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.