Thank you so much. This indeed works! But I want to make sure I understand how and why this works. Here is my breakdown of how I think it is functioning. But I'm stumped why add the data[0].length. What is that doing that just data.length doesn't do?

if (mealSkip === true) {
  row[2] = false; // Updates the "data" variable above within just this script.
  activePage.getRange(2,1,data.length, data[0].length).setValues(data); // Takes the updated "data" from this script and applies it to the whole row.
  console.log("Set mealSkip to equal FALSE"); // DEBUGGING LOGS

  // activePage.getRange(2,1,data.length, data[0].length).setValues(data);
  // ^ The active spreadsheet, called at the top of this function
  //           ^ getRange(row, column, numRows, numColumns) 
  //           ^ https://developers.google.com/apps-script/reference/spreadsheet/sheet#getRange(Integer,Integer,Integer,Integer)
  //                    ^ 2 = Unlike the row[#] above, THESE rows count starts at 1, so to skip the first row, we start at 2.
  //                       ^ 1 = The first column. Since we don't skip the first column, it is set to 1. 
  //                         ^ data.length = "data" is the variable established at the top of this function
  //                         ^ data.length = "length" is a property that returns an int that is the amount of rows for this range.
  //                                      ^ data[0].length = Same as above, except the [0] ?????
  //                                                     ^ setValues(data) = This will update all the cells in this row with the "data" variable, including any changes we applied via the script. 
}