Calorie density dieting is half-right for lifters — the trap is 1,400 calories
In short
The volumetrics approach sorts food by calories per gram and builds the diet around low-density foods under 0.6. In a small 12-week study it produced weight loss comparable to time-restricted eating. But the plan's stated target for weight loss is 1,400 calories a day, and dietitians note it is a poor fit for athletes with high energy needs. What lifters should take from it is the classification tool, not the calorie figure.
The volumetrics diet was set out in 2000 by Barbara Rolls, a nutrition science researcher at Penn State. The idea is simple: sort food by calories per gram, then fill your stomach with the low-density items — the ones that are mostly water and fibre. You eat the same volume, take in fewer calories, and end up equally full.
How is food classified?
- Category one (under 0.6) — the bulk of the diet. Berries, melons, broccoli, beets, carrots, nonfat yoghurt, skim milk, broth-based soups.
- Category two (0.7–1.5) — in moderation. Skinless chicken, lean beef, lentils, chickpeas, potatoes, squash, brown rice, quinoa.
- Category three (1.6–3.9) — smaller amounts. Fatty meat and fish, cheese, whole milk, pasta, white bread.
- Category four (4–9) — sparingly. Nuts, seeds, oils, fast food, candy.
Nothing is off-limits, which is the approach's real strength. Because it adjusts proportions rather than banning foods, it holds up better than a crash diet. There is evidence behind it too: in a small study of people with overweight or obesity, it produced weight loss comparable to time-restricted eating, with both groups showing significant reductions after 12 weeks.
Where does it fall down?
Two criticisms. First, it villainises healthy fats — nuts and seeds land in category four, when every diet needs some proportion of fat. Second, the sorting is by calorie density alone, not food quality. That puts margarine and crisps in the same category as nuts and seeds.
Why is it a poor fit for lifters?
This is the crux. The plan suggests 1,400 calories a day for weight loss, plus 30 to 60 minutes of daily exercise. For someone training heavy three to five times a week, 1,400 is less a deficit than an attrition rate. The dietitians quoted say as much: it is not a good fit for people with high energy needs like endurance athletes, and the high-bulk foods can be difficult for anyone with gut issues.
The bulk itself is a problem too. Fill your stomach with low-density food and hitting 1.6–2.2g of protein per kg of bodyweight becomes physically awkward. Being full while still short on protein, repeated daily, is how a cut turns into muscle loss.
So what should you take from it?
Take the classification tool, not the calorie target. Set protein and total calories against your training load first, then within that budget push the share of low-density foods — vegetables, fruit, broth-based soups — upward. The result is a far more filling diet at the same calories, and that is what actually determines whether a cut survives past week three.
In a deficit, protein comes before volume. Place your protein first and fill the remaining capacity with vegetables and soups, rather than filling up on low-density food and finding no room left.
How this relates to your strength score
There is a trap here worth naming. A relative strength score is corrected for bodyweight, so losing weight raises your score even if your lifts do not move. During a cut the score can therefore travel in the opposite direction to your actual strength — your squat drops 5kg, your bodyweight drops 4kg, and the score goes up. That is why a cut has to be judged on the absolute Big 3 numbers alongside the score. Weight falling while the lifts hold means the cut is working. Both falling together means calories or protein are too low.
On protein intake itself, see why digestive enzyme supplements do not help you absorb more protein.
Frequently asked questions
What is the volumetrics or calorie density diet?
It sorts food by calories per gram and builds meals around low-density foods high in water and fibre. Set out by Barbara Rolls in 2000, it bans nothing and adjusts proportions instead. Its stated weight-loss target is 1,400 calories a day plus 30–60 minutes of daily exercise.
Does calorie density dieting work?
In a small study of people with overweight or obesity it produced weight loss comparable to time-restricted eating, with both approaches showing significant reductions after 12 weeks. Because it adjusts proportions rather than banning foods, it is considered easier to sustain.
Should lifters follow it as written?
Not as written. The 1,400 calorie target is far too low for someone training heavy, and dietitians note the approach is a poor fit for athletes with high energy needs. Set calories against your training load and borrow only the calorie-density classification.
What are the drawbacks of this diet?
It over-restricts healthy fats, and it sorts by calorie density rather than food quality — which places margarine and crisps in the same category as nuts and seeds. The high-bulk approach can also be difficult for people with gut issues.
If my strength score rises during a cut, is that good?
Not necessarily. A bodyweight-corrected score rises when weight falls, even if your lifts do not improve, so the score can climb while strength is actually declining. During a cut, check the absolute Big 3 numbers alongside the score.
Source: Men's Health Nutrition