What the Zone Diet Block Calculator does
This calculator works out your daily Zone diet blocks from your lean body mass and activity level: how many blocks to eat a day, the grams of protein, carbohydrate and fat they stand for, and a split across three meals and two snacks that you can print. If you do not know your body fat percentage, it estimates it from a few tape-measure readings with the US Navy formula.
The Zone diet, created by Barry Sears, sizes protein to the lean (fat-free) part of your body and then matches every 7 g of protein with 9 g of carbohydrate and 1.5 g of added fat, roughly a 40/30/30 split of calories. One set of those amounts is a "block". Everything here follows the method as the diet publishes it, shows every step, and is an estimate - not dietary or medical advice.
How to use it
- Choose female or male and enter your weight in kilograms or pounds.
- Pick the activity level that matches a normal week. Each level carries an activity factor - grams of protein per pound of lean body mass - shown in the list.
- Enter your body fat percentage if you know it. Otherwise choose "Estimate from measurements" and enter height, neck and waist (and hips for women) in centimetres or inches.
- Tick the vegetarian box if most of your protein comes from plant foods, which have little fat of their own; each block then uses 3 g of added fat instead of 1.5 g.
- Read your daily blocks and the meal split, then print it or copy it. Tick "Remember" to keep the details in this browser only.
Reading the results
Blocks per day is the main figure. A meal of 3 blocks is 21 g of protein, 27 g of net carbohydrate and 4.5 g of added fat; a snack is usually one block.
If the calculation gives fewer blocks than the diet's minimum - 11 a day for women and 14 for men - the minimum is used and the page says so. Many people land on the minimum.
The energy figure counts only the block amounts. Protein foods such as eggs, meat and dairy carry some fat of their own, so real intake is somewhat higher; the diet is still lower in calories than most people's usual eating.
Lean body mass drives everything, so a body fat estimate that is off by a few points changes the result by a block or so. A measured figure from calipers, a scale or a DEXA scan is better than the tape-measure estimate.
Worked example: an active man, 180 lb, with tape-measure readings
Height 70 in, neck 15 in, waist 34 in. US Navy formula: 86.010 x log10(34 - 15) - 70.041 x log10(70) + 36.76 = 109.99 - 129.23 + 36.76 = 17.5% body fat.
Lean body mass = 180 x (1 - 0.175) = 148.5 lb. At the "active" factor of 0.8 g per lb he needs 148.5 x 0.8 = 118.8 g of protein a day.
118.8 / 7 = 16.97, which rounds to 17 blocks: 119 g protein, 153 g carbohydrate and 25.5 g added fat.
Split as two one-block snacks and 15 blocks across three meals of 5 blocks each - about 35 g of protein per meal. A 68 kg woman at 30% body fat and moderate activity works out at 10.5 blocks, so she uses the 11-block minimum: three 3-block meals and two snacks.
Formulas and scoring rules
- Lean body mass
LBM (lb) = weight (lb) x (1 - body fat % / 100)1 lb = 0.45359237 kg exactly.- Protein need
protein (g/day) = LBM (lb) x activity factorActivity factors from 0.5 (sedentary) to 1.0 (athlete) g per lb, as commonly published for the Zone method.- Daily blocks
blocks = round(protein / 7), at least 11 for women and 14 for men- Grams per block
7 g protein + 9 g carbohydrate (minus fibre) + 1.5 g fat (3 g with vegetarian protein)- US Navy body fat, men (inches)
%BF = 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76- US Navy body fat, women (inches)
%BF = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387Measurements in centimetres are converted at 2.54 cm per inch. Body fat is shown to 0.1%.
Turning blocks into food
A block is defined by grams, so turning it into food means reading labels or a block list. As a rule of thumb, a protein block is about an ounce (28 g) of cooked lean meat or fish, because lean meat is roughly a quarter protein by weight. For carbohydrate, use the label's total carbohydrate minus fibre: 9 g of net carbohydrate is a small portion of rice, bread or fruit but a large one of leafy or green vegetables, which is why the diet leans on vegetables. A fat block of 1.5 g is a small amount - a few nuts or a splash of oil. The diet's own food block guide lists foods by block; this page gives the totals, not a food list.
Because protein is sized to lean mass rather than body weight, two people of the same weight can need quite different amounts: the leaner person gets more blocks. That is the main way the Zone differs from a fixed 40/30/30 calorie split.
Limitations: what the result does not prove
- It is an estimate built on the Zone diet's own conventions. Its health claims are debated, and this page makes none of them.
- It is not dietary or medical advice. Pregnancy, breastfeeding, diabetes, kidney disease, eating disorders and teenage growth all change what you should eat; talk to a doctor or registered dietitian.
- The US Navy formula is a field estimate with an error of a few percentage points, larger for very muscular or very lean people.
- Block grams are targets for added macronutrients; they do not count fibre, alcohol or the fat naturally present in protein foods.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- Zone Labs - Zone Food Block Guide (block definitions, 11 and 14 block averages)
- Hodgdon and Beckett (1984), Prediction of percent body fat for U.S. Navy men from body circumferences and height - Naval Health Research Center report 84-11
- Zone Labs - Zone diet explained
Frequently asked questions
How many Zone blocks should I eat a day?
Divide your daily protein need - lean body mass in pounds times your activity factor - by 7. Most women land at or near the 11-block minimum and most men at 14 to 17 blocks. Enter your details and the calculator does the arithmetic and the meal split.
What is one block in the Zone diet?
One protein block (7 g of protein), one carbohydrate block (9 g of net carbohydrate) and one fat block (1.5 g of added fat, or 3 g if the protein is vegetarian), eaten together. Every meal and snack keeps the three in a 1:1:1 ratio.
How many Zone blocks for a woman?
The diet's guides give 11 blocks a day as the average for women - three 3-block meals and two 1-block snacks - and use it as the minimum. Taller, leaner or more active women can need more; the calculator shows when the minimum is being applied.
How do I calculate lean body mass for the Zone diet?
Multiply your weight by one minus your body fat percentage. At 180 lb and 17.5% body fat, lean mass is 180 x 0.825 = 148.5 lb. If you do not know your body fat, the US Navy tape-measure estimate here needs only height, neck, waist and, for women, hips.
Is the Zone diet the same as a 40/30/30 diet?
It aims at about 40% of calories from carbohydrate, 30% from protein and 30% from fat, but it sets the amounts from lean body mass and builds meals in blocks. A plain 40/30/30 calculator starts from calories instead, so the two can give different gram targets.
Can vegetarians follow the Zone diet blocks?
Yes. Plant proteins such as tofu, tempeh and protein powder contain little fat of their own, so the diet doubles the fat block to 3 g. Tick the vegetarian box and the meal split uses 3 g of added fat per block.
Last reviewed by the A2Z.Tools team against the sources listed above.
