{laugh} Excel would be a bit of overkill, but thank you for the suggestion. As far as the progress goes, it hasn't even been all that difficult: I've simply been experimenting with what it's like to feel different degrees of hunger, just being curious about it. I realized that it's been years since I've actually felt hungry (yeah... sounds crazy, I know), and I know that it won't kill me to experience it. As a side benefit, food now tastes absolutely amazing, and I get really full on a dollar's worth of salad greens. It feels fantastic.

Regarding your code: bravo! That's pretty much what I was looking for - it's very readable, and the algorithm even makes sense to me. I've been playing around with my own code in the meantime, and came up with something more-or-less similar (except I handle the _end_ case as the special one.)

use POSIX qw/strftime/;
use strict;
$|++;

use constant Intervals => 20;

my ($prev_time, $prev_val, $tmin, $tmax, $last_val, @curve);
open my $data, "weightdata.txt" or die "weightdata.txt: $!\n";
while (<$data>){
    chomp;
    next unless m{^\s*([\d/]+)\s+([\d.]+)};
    my($m, $d, $y) = split /\//, $1;
    my $time_point = strftime("%s", 0, 0, 0, $d, $m - 1, $y - 1900);
    if (defined $prev_time){
        my $slope = ($2 - $prev_val) / ($time_point - $prev_time);
        push @curve, [ $prev_time, $time_point, $prev_val, $slope ];
    }
    ($prev_time, $prev_val) = ($time_point, $2);
    ($tmax, $last_val) = ($time_point, $2);
}
close $data;

$tmin = $curve[0][0];
my $interval = ($tmax - $tmin) / (Intervals - 1);

my ($prev_t, $val, $slope);
for my $t (0 .. Intervals - 2){
    my $calc_t = $t * $interval + $tmin;
    shift @curve unless $calc_t >= $curve[0][0] && $calc_t <= $curve[0
+][1];
    ($prev_t, $val, $slope) = @{$curve[0]}[0, 2, 3];
    printf "%2d: Weight on %s was %.1f\n", $t + 1, strftime("%F",local
+time($calc_t)),
        ($calc_t - $prev_t) * $slope + $val;
}
printf "%2d: Weight on %s was %.1f\n", Intervals, strftime("%F",localt
+ime($tmax)), $last_val;
[download]

I've even looked at the intervals carefully - they're consistent - and the change in weight from one plotted point to another (yep, looks right.) I just might be getting the hang of this process. :)

Thanks very much for your response; I'm definitely finding all this highly educational.