Methodology

How VEXO calculates your nutrition targets

VEXO gives you a daily calorie target and targets for protein, fat, carbohydrate and fiber. This page explains how VEXO calculates those numbers, the published evidence the methodology uses, and the product choices VEXO makes where the evidence supports more than one reasonable approach.

We would rather show you the uncertainty than hide it. Where the research gives a range, we tell you the range and the number we picked.

Not every VEXO number represents a precise biological requirement. Some values are evidence-based estimates; others are transparent product-policy choices made within an evidence-supported range. We distinguish between the two throughout this page.

VEXO is a general-wellness service. This page explains its nutrition-target methodology; it is not medical advice or medical nutrition therapy.

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What information does VEXO use?

Your age, sex (used to choose the energy equation), height, current weight, activity level, goal, and, for weight-change goals, your target weight. For fat loss, your chosen rate of loss also matters.

VEXO does not require body-fat percentage or lean-mass estimates. Consumer body-composition methods can have meaningful individual-level error, so requiring those estimates could add noise rather than improve a deterministic target. [11]

How is my calorie target calculated?

Step 1: Estimate your maintenance calories. VEXO uses the Estimated Energy Requirement (EER) equations published by the National Academies of Sciences, Engineering, and Medicine in 2023. These equations were developed using data that include doubly labeled water measurements, a benchmark reference method for measuring free-living total energy expenditure. They use sex, age, height, weight, and physical activity level to estimate the energy needed to maintain energy balance. [1]

Your activity level is one of four categories: Inactive, Low Active, Active, or Very Active. If you are not sure, choose the lower activity level.

Step 2: Adjust for your goal.

For Fat Loss, you choose a target weight and timeline in weeks. VEXO calculates the target weekly rate implied by those selections, as a percentage of your current body weight, and uses that rate to select the starting calorie adjustment:

Research has not established one optimal calorie surplus for muscle gain. In resistance-trained lifters, a recent comparison of smaller and larger surpluses found that faster weight gain was associated more clearly with additional skinfold gain than with greater muscle growth. VEXO therefore begins with a deliberately conservative 5% surplus. [2, 3]

The fat-loss percentages are a starting point, not a guarantee of a particular rate of loss. Everyone responds differently.

How accurate is my calorie target?

Your calorie target is an estimate based on published equations, not a measurement of your metabolism or energy expenditure. The National Academies' equations were developed and evaluated using large datasets, but individual prediction error remains meaningful. A person's actual daily energy expenditure can differ from the estimate by hundreds of calories. One practical way to assess how well the estimate fits you is to look at your weight trend over several weeks. [1]

How is my protein target calculated?

Protein is calculated from your VEXO reference weight and your goal:

VEXO calculates in kilograms and rounds to the nearest gram, so the per-pound figures above are approximate.

Example: a person weighing 130 lb with a muscle-gain goal: 130 lb is 58.97 kg, times 1.8, is about 106 g of protein a day.

Which weight is used? VEXO currently uses your current weight unless you have a target weight below your current weight that passes VEXO's target-weight checks, in which case VEXO uses that lower target weight. For a muscle-gain goal, the target weight is above current weight, so current weight is used.

This reference-weight rule is a VEXO operational choice, not an evidence-established physiological formula. It is intended to limit protein from scaling directly with a higher current body weight when a lower accepted target exists. VEXO is actively reviewing whether a different reference-weight method would better match the evidence across different body sizes and body-composition profiles.

Why isn't my protein target 1 gram per pound?

One gram per pound is a common fitness rule. VEXO does not treat it as a universal protein requirement.

In a widely cited 2018 systematic review and meta-analysis of 49 resistance-training studies involving 1,863 participants, the estimated protein-intake breakpoint for additional gains in fat-free mass was approximately 1.62 g/kg/day, or about 0.74 g/lb/day. [4]

That estimate was uncertain: the 95% confidence interval around the estimated breakpoint extended from approximately 1.03 to 2.20 g/kg/day. VEXO therefore does not treat 1.62 g/kg/day as a universal physiological cutoff. [4]

VEXO therefore treats the research as a range rather than a single physiological cutoff. For Muscle Gain, VEXO uses 1.8 g/kg/day, about 0.82 g/lb/day, as an evidence-informed deterministic product target above the central estimate but below the upper-end hedge.

1.8 g/kg is not a precisely established physiological requirement, and research has not demonstrated that it is superior to every other intake within the supported range.

In one 16-week randomized study of resistance-trained men, reported protein intakes around 3.2 g/kg/day did not produce greater lean-mass or strength gains than approximately 1.6 g/kg/day for most measured outcomes. [5] That does not establish that higher protein can never benefit an individual, but it does not support assuming that substantially higher protein necessarily produces greater muscle or strength gains.

Why is protein higher for fat loss than for muscle gain?

During weight loss, preserving lean mass becomes more challenging. Higher protein intake can improve muscle-mass retention during energy restriction, particularly when combined with resistance training and in contexts where lean-tissue preservation is a priority. [6]

The exact optimal amount varies with leanness, deficit size, and training status. There is no general evidence-based principle that a calorie surplus requires more protein than a deficit.

Are the targets different for women?

VEXO uses sex-specific National Academies equations when estimating energy requirements. [1]

VEXO does not currently use separate protein, fat, or carbohydrate coefficients by sex because the cited evidence does not establish a validated basis for separate daily coefficients within VEXO's general-wellness methodology. [7, 8]

That does not mean biological differences do not exist. Women remain underrepresented in sports-nutrition research, particularly across menstrual, perimenopausal, and postmenopausal stages, and VEXO will revisit the methodology as stronger evidence becomes available.

Do the targets change with age?

Age is already part of VEXO's calorie calculation. VEXO does not currently apply a separate protein multiplier at age 40 or solely because someone is peri- or post-menopausal.

Aging can affect the anabolic response to protein and resistance exercise, but current evidence does not establish a validated age-40 or menopause-specific multiplier for total daily protein. The protein intakes discussed in the cited literature for active adults and middle-aged or older women overlap the range of VEXO's current targets. [8, 9]

If stronger evidence eventually supports age- or menopause-specific total-protein targets, VEXO will re-review the methodology.

How are fat and carbohydrate calculated?

After protein is set:

• Fat starts at 25% of your calories, within the 20% to 35% range recommended for adults. For 18-year-olds, the minimum is 25%, following the dietary guideline range for that age. [10]
• Carbohydrate receives the remaining calories, subject to VEXO's standard-plan minimum of 130 g/day. The 130 g value is the adult carbohydrate RDA; VEXO uses it as a balanced-plan design criterion, not as a medical safety threshold or a sports-performance target. [10]

VEXO never reduces your approved protein target to make the numbers fit. If protein and VEXO's 130 g standard-plan carbohydrate minimum do not both fit within your calorie target, VEXO first lowers fat toward its applicable minimum. If they still do not fit, VEXO raises the calorie target in 25-calorie increments until they do.

VEXO's standard daily carbohydrate target is not an endurance-event fueling prescription. For prolonged endurance exercise, meta-analytic evidence has found an average performance benefit from carbohydrate consumed during exercise, with the effect varying by exercise duration and protocol. [12] People doing long or high-volume endurance training may need sport-specific fueling guidance beyond their standard VEXO target.

How is fiber calculated?

VEXO sets fiber at 14 g for every 1,000 calories in your target, consistent with the Dietary Reference Intake basis cited below. [10]

Is there a minimum calorie target?

Yes. For every goal, VEXO applies an absolute product floor: 1,200 calories per day when VEXO uses the female energy equation and 1,500 when it uses the male energy equation. For Fat Loss, a second limit also applies: the target will not be set below 80% of estimated maintenance. When both limits apply, the higher number governs.

These are VEXO product guardrails, not clinical minimum calorie requirements.

Who should not rely on VEXO's automated nutrition targets?

VEXO is a general-wellness service for adults age 18 and older. Maintenance and Performance nutrition targets are available beginning at age 18; automated Fat Loss and Muscle Gain targets begin at age 19. VEXO's nutrition targets are general-wellness estimates, not medical advice, diagnosis, treatment, or medical nutrition therapy.

Do not rely on VEXO's automated nutrition targets without direct supervision from a qualified professional if you are pregnant or breastfeeding; have a current or prior eating disorder or history of disordered eating; are underweight; take medication or have a medical condition that affects diet, metabolism, or weight; require individualized nutrition management; have been directed by a clinician to follow a restricted diet; or have been advised not to restrict calories, pursue weight change, or track calories or weight. Follow your clinician's guidance.

Where do these numbers come from?

1. 1. National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Energy. Washington, DC: The National Academies Press; 2023. doi:10.17226/26818
2. 2. Helms ER, Spence A-J, Sousa C, Kreiger J, Taylor S, Oranchuk DJ, Dieter BP, Watkins CM. Effect of small and large energy surpluses on strength, muscle, and skinfold thickness in resistance-trained individuals: a parallel groups design. Sports Medicine - Open. 2023;9(1):102. doi:10.1186/s40798-023-00651-y
3. 3. Slater GJ, Dieter BP, Marsh DJ, Helms ER, Shaw G, Iraki J. Is an energy surplus required to maximize skeletal muscle hypertrophy associated with resistance training? Frontiers in Nutrition. 2019;6:131. doi:10.3389/fnut.2019.00131
4. 4. Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SM. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. 2018;52(6):376-384. doi:10.1136/bjsports-2017-097608
5. 5. Bagheri R, Kargarfard M, Sadeghi R, Scott D, Camera DM. Effects of 16 weeks of two different high-protein diets with either resistance or concurrent training on body composition, muscular strength and performance, and markers of liver and kidney function in resistance-trained males. Journal of the International Society of Sports Nutrition. 2023;20(1):2236053. doi:10.1080/15502783.2023.2236053
6. 6. Kokura Y, Ueshima J, Saino Y, Maeda K. Enhanced protein intake on maintaining muscle mass, strength, and physical function in adults with overweight/obesity: a systematic review and meta-analysis. Clinical Nutrition ESPEN. 2024;63:417-426. doi:10.1016/j.clnesp.2024.06.030
7. 7. Mercer D, Convit L, Condo D, Carr AJ, Hamilton DL, Slater G, Snipe RMJ. Protein requirements of pre-menopausal female athletes: systematic literature review. Nutrients. 2020;12(11):3527. doi:10.3390/nu12113527
8. 8. Sims ST, Kerksick CM, Smith-Ryan AE, Janse de Jonge XAK, Hirsch KR, Arent SM, et al. International Society of Sports Nutrition position stand: nutritional concerns of the female athlete. Journal of the International Society of Sports Nutrition. 2023;20(1):2204066. doi:10.1080/15502783.2023.2204066
9. 9. Bagheri R, Ghobadi H, Mansordehghan M, Camera DM, Kargarfard M. Resistance versus concurrent training with three assigned protein targets in middle-aged and older women: a randomized 2 × 3 factorial trial. Journal of the International Society of Sports Nutrition. 2026;23(1):2720742. doi:10.1080/15502783.2026.2720742
10. 10. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005. doi:10.17226/10490
11. 11. Oliver CJ, Del Vecchio L, Minehan M, Climstein M, Rosic N, Myers S, Tinsley G. The validity of bioelectrical impedance analysis compared to a four-compartment model in healthy adults: a systematic review. Journal of Functional Morphology and Kinesiology. 2026;11(1):65. doi:10.3390/jfmk11010065
12. 12. Ramos-Campo DJ, Clemente-Suárez VJ, Cupeiro R, Benítez-Muñoz JA, Andreu-Caravaca L, Rubio-Arias JÁ. The ergogenic effects of acute carbohydrate feeding on endurance performance: a systematic review, meta-analysis and meta-regression. Critical Reviews in Food Science and Nutrition. 2024;64(30):11196-11205. doi:10.1080/10408398.2023.2233633

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