The Food Index is made up of a weighted average of all of the current foods listed in the Market Watch, with the starting date of this average on 12 January 2008, at an index of 100. The overall rising and falling of food prices is reflected in this index.
While specialised for just watching food prices, it is set up and adjusted in a manner similar to the Common Trade Index, and the divisor may be adjusted to include new food added by Jagex (see the FAQ for more information).
As of today, this index is 462.69 1.93
Any suggested changes to this index should be added to the talk page.
 Start date: 12 January 2008 (at index of 100)
 Index today: 462.69
 Change today: 1.93
 Number of items: 19 (last adjusted on 12 January 2008)
 Index divisor: 19.0000 (last adjusted on 12 January 2008)
This is the current list of items included in this index:
Icon  Item  Price  Direction  Low Alch  High Alch  Limit  Members  Details  Last updated 

 Salmon  87   35  52  10,000   view  7 hours ago 
 Tuna  137   48  72  10,000   view  7 hours ago 
 Lobster  149   107  160  10,000   view  7 hours ago 
 Bass  733   108  162  10,000   view  7 hours ago 
 Swordfish  172   160  240  10,000   view  7 hours ago 
 Monkfish  379   92  138  10,000   view  7 hours ago 
 Shark  851   120  180  10,000   view  7 hours ago 
 Cavefish  1,201   140  210  10,000   view  7 hours ago 
 Rocktail  2,162   240  360  10,000   view  7 hours ago 
 Great white shark  1,402   130  195  10,000   view  7 hours ago 
 Bread  482   9  14  1,000   view  7 hours ago 
 Cake  606   20  30  1,000   view  7 hours ago 
 Chocolate cake  942   28  42  1,000   view  7 hours ago 
 Strawberries (5)  1,931   1  1  10,000   view  7 hours ago 
 Saradomin brew (4)  7,737   80  120  1,000   view  7 hours ago 
20 May 2015

 Adjusted index: Food Index
 Adjustment date: 20 May 2015
 Affected templates: Template:GE Food Index and Template:GE Food Index/Diff
 Added item(s): 7 — Bread, Cavefish, Great white shark, Rocktail, Salmon, Saradomin brew (4), Strawberries (5)
 Removed item(s): 11 — Admiral pie, Garden pie, Kebab, Manta ray, Redberry pie, Roast bird meat, Sea turtle, Stew, Sweetcorn, Ugthanki kebab, Wild pie
 Items before adjustment: 19
 Items after adjustment: 15
 Divisor before adjustment: 19.0000
 Divisor after adjustment: 8.7619
Item

Base date

Base price

Price on adjustment date

Comments

Lobster

25 January 2008

175

196

Unchanged

Bass

195

225

Tuna

81

163

Swordfish

272

295

Monkfish

233

336

Shark

657

739

Cake

52

91

Chocolate cake

150

421

Ugthanki kebab

887

810

Removed item

Kebab

32

276

Sea turtle

1,264

2,690

Manta ray

1,794

1,907

Sweetcorn

135

43

Roast bird meat

22

19

Admiral pie

1,031

497

Wild pie

3,491

985

Redberry pie

381

1,280

Garden pie

657

475

Stew

100

1,102

Bread

–

–

433

Added item

Strawberries (5)

318

Saradomin brew (4)

9,762

Salmon

80

Cavefish

1,256

Rocktail

1,814

Great white shark

912

Calculations
From the old divisor obtained from the templates:
 ${div}_{\text{old}}=19.0000$
We need to calculate a new divisor:
 ${div}_{\text{new}}={div}_{\text{old}}\times {\frac {\sum \left({\frac {p}{q}}\right)_{\text{new}}}{\sum \left({\frac {p}{q}}\right)_{\text{old}}}}$
To calculate the new divisor, we need to find:
 ${\begin{aligned}\sum \left({\frac {p}{q}}\right)_{\text{old}}&={\text{sum of ratios prior to change}}\\&={\text{sum of unchanged ratios}}+{\text{sum of removed ratios}}\\&=\left({\frac {196}{175}}+{\frac {225}{195}}+\dots +{\frac {421}{150}}\right)+\left({\frac {810}{887}}+{\frac {276}{32}}+\dots +{\frac {1,102}{100}}\right)\\&=42.27255853{\text{ (up to 8 d.p.)}}\end{aligned}}$
And also:
 ${\begin{aligned}\sum \left({\frac {p}{q}}\right)_{\text{new}}&={\text{sum of ratios prior to change}}{\text{sum of removed ratios}}+{\text{sum of added ratios}}\\&=\sum \left({\frac {p}{q}}\right)_{\text{old}}{\text{sum of removed ratios}}+{\text{number of added items}}\\&=42.27255853\left({\frac {810}{887}}+{\frac {276}{32}}+\dots +{\frac {1,102}{100}}\right)+7\\&=19.49428715{\text{ (up to 8 d.p.)}}\end{aligned}}$
Thus, the new divisor is:
 ${\begin{aligned}{div}_{\text{new}}&={div}_{\text{old}}\times {\frac {\sum \left({\frac {p}{q}}\right)_{\text{new}}}{\sum \left({\frac {p}{q}}\right)_{\text{old}}}}\\&=19.0000\times {\frac {42.27255853}{19.49428715}}\\&=8.7619{\text{ (4 d.p.)}}\end{aligned}}$
