1-2 weeks? That seems dangerously optimistic to me.
US Government is currently recommending citizens have enough food and water for 2 weeks for every member: https://www.ready.gov/pandemic
This isn't a new page it's their advice for being prepared in general for a pandemic.
Here's a similar page put together by the CDC: https://cchealth.org/pandemic-flu/pdf/individuals_and_famili...
Latter-day Saint here. This indeed was a teaching of the Church for quite some time, not so much anymore as it has shifted to general emergency preparedness [1][2][3][etc]. Some indeed still keep decent food stores though, we can order cases of #10 cans for varying things from the Church online [4] (the general public can too).
Some people keep a lot of freeze dried stuff, some can their excess that they grow, others just keep a lot of staples on hand that they rotate through. Personally I can feed myself for a few months on freeze dried stuff and 10-30 year canned staples then another 1-2 months on stuff I rotate through and eat daily (beans, oats).
[1] - https://www.churchofjesuschrist.org/study/manual/gospel-topi...
[2] - https://newsroom.churchofjesuschrist.org/article/preparednes...
[3] - https://www.churchofjesuschrist.org/church/news/church-annou...
[4] - https://store.churchofjesuschrist.org/ click all categories, food storage (direct linking to the page will often generate errors)
Americans are well prepared... Even if they haven't tried to be.