The cost of popular diets, compared
We estimated the weekly grocery cost of 12 popular diets for one adult at ~2,000 kcal/day. Carnivore is the priciest at about $115/week — roughly 1.9× the cost of intermittent fasting ($60/week). Sort and filter the full comparison below. Prices updated August 2026.
| # | Diet | Per week | Per day | Per month |
|---|---|---|---|---|
| 1 | Intermittent fasting Structured Fewer meals means less total food; the cost depends on what you eat in the window. | $60 | $8.57 | $261 |
| 2 | Vegetarian Plant-based Beans, lentils, eggs, grains and seasonal veg are cheap; cheese and meat substitutes add up. | $62 | $8.86 | $269 |
| 3 | Vegan Plant-based Cheapest built on legumes, rice and tofu; plant milks and mock meats push it higher. | $66 | $9.43 | $287 |
| 4 | Standard / balanced Balanced A typical mixed diet — the baseline everything else is compared against. | $75 | $10.71 | $326 |
| 5 | DASH Balanced Lots of produce, whole grains, lean protein and low-fat dairy. | $80 | $11.43 | $348 |
| 6 | Mediterranean Balanced Fish, olive oil, nuts and produce cost more than grains and beans. | $85 | $12.14 | $369 |
| 7 | Low-carb Low-carb / high-fat More meat and eggs, fewer cheap grains and legumes to bulk out meals. | $90 | $12.86 | $391 |
| 8 | Pescatarian Balanced Fish and seafood are among the most expensive proteins per gram. | $92 | $13.14 | $400 |
| 9 | Paleo Low-carb / high-fat Meat, nuts and produce with no cheap grains, beans or dairy to fall back on. | $100 | $14.29 | $435 |
| 10 | Keto Low-carb / high-fat Meat, cheese, oils and low-carb produce; almost no cheap filler calories. | $102 | $14.57 | $443 |
| 11 | Whole30 Structured Meat and produce only — no grains, legumes, dairy, sugar or convenience foods for 30 days. | $105 | $15.00 | $456 |
| 12 | Carnivore Low-carb / high-fat All animal foods; meat is the most expensive way to buy calories. | $115 | $16.43 | $500 |
12 diets · estimated grocery cost for one adult at ~2,000 kcal/day, US average retail prices.
Key findings
Cheapest (Intermittent fasting, Vegetarian, Vegan). Eating less often, or building meals on legumes, grains and eggs instead of meat, is what keeps a food budget down. Plant-forward diets are cheap precisely because plants are the cheapest source of calories and protein.
Most expensive (Carnivore, Whole30, Keto). Meat-heavy, grain- and legume-free diets cost the most — they swap the cheapest calories for the priciest ones and cut out low-cost fillers. The single biggest lever on any diet’s cost is how you buy protein.
Make any diet cheaper
Most of a diet’s cost is protein — so buying the best-value protein shrinks any grocery bill. See the companion studies on the cheapest protein sources and the leanest protein, then let ProperDietPlan build a personalized meal plan for your diet and budget — with easy swaps and a shopping list.
Build my meal plan →Frequently asked questions
What is the cheapest diet?
By weekly grocery cost, plant-forward and meal-timing approaches are cheapest — intermittent fasting, vegetarian and vegan diets built on legumes, grains and eggs. Carnivore, Whole30, keto and paleo are the most expensive because they lean on meat and exclude cheap fillers like grains and beans.
How much does keto cost vs a normal diet?
In our estimate, keto runs about $100+ per week for one adult vs about $75 for a standard balanced diet — roughly 35% more — because it replaces cheap carbohydrate calories (rice, pasta, beans, bread) with meat, cheese and oils. Carnivore is higher still.
How did you estimate these costs?
Each figure is the grocery cost for one adult eating about 2,000 calories a day on a representative food basket for that diet, at US national-average retail prices. They are ballpark comparisons, not exact numbers — real cost varies a lot by region, brand, season and how much you cook from scratch versus buy convenience versions.
Can I make an expensive diet cheaper?
Yes. Most of the cost is protein, so buying the best-value protein makes any diet cheaper. See our companion study on the cheapest protein sources (protein per dollar), and let ProperDietPlan build a plan around budget-friendly foods.
Methodology & sources
Each figure is the estimated grocery cost for one adult eating ~2,000 kcal/day on a representative food basket for that diet, at US national-average retail prices (August 2026). These are deliberately transparent estimates: real cost varies a lot by region, brand, season and how much you cook from scratch versus buy convenience or branded versions (mock meats, keto snacks, bottled dressings). Treat them as relative comparisons between diets, not a precise figure for any one person. Protein-cost figures underlying the comparison use USDA FoodData Central values (see our protein-per-dollar study).
Free to reuse with attribution — please link back to this page (properdietplan.com/en/research/cost-of-popular-diets).
General educational information, not medical or financial advice. See our Editorial Policy.