Seems I misread that chart. It says exercise per 10 minutes. Anyway, I found a more appropriate chart: http://whatscookingamerica.net/Information/CalorieBurnChart.htm, which shows the number of calories burned per minute, which was what I was searching for in the first place.
According to the second chart, I'd be burning .036 calories per minute x my weight of 213 lbs = 7.668 calories per minute by walking at a normal pace on asphalt pavement. Given that, 160 minutes of walking per week should burn 1,226.88 calories per week, or roughly less than half a pound per week. Seems a bit low to me, as I've been burning more fat that this just sitting at my computer. I ate a sirloin steak just a couple of hours ago and I can already smell ketone waste in my urine, so I know I'm burning body fat just sitting here typing this. But then, maybe my metabolism is a little different than most people's. It seems a high amount of dietary protein significantly increases my metabolic rate. This makes sense to me, as I was a skinny kid and, back then, ate mostly meat because I didn't like veggies much. If my theory is correct, I should do better than a mere 7.668 calories per minute, thus I'll lose fat quicker the chart projects. This may be due to the extra muscle mass I gained during the nineties, as well. The more lean muscle you have, the more fat you can burn and the less effort it takes to do so.
Given all that, I'll at least round up the calories per minute to 8 and say that, for 160 minutes of walking per week, I'd burn 1,280 calories per week, which still seems low, though, checking with some other sources, most seem to say about 7 calories per minute. The factor they are not including is one's starting weight, however. The more you weigh, to begin with, the more calories per minute you'll burn because you're doing more work to move a heavier mass than someone who weighs less.
Using the calorie calculator I found at http://www.primusweb.com/fitnesspartner/jumpsite/calculat.htm, I determined I'd be burning about 1,290 calories per week, so I guess there is no arguing with the math, especially since this calculator takes your weight into account. Okay, then. So, at that rate, I'll lose a pound every two weeks or so. That's just for the effort expended during exercise, though. It doesn't account for the fat I'm obviously still burning while at rest, as a result of having more stored body fat than my body can find calories to maintain. That has to be considered, as well. It's hard to calculate how much that is, as I've been walking daily more or less since I started the Paleo Diet, thus, my walking has been adding to my calorie burning.
Another way of getting to a reasonable estimate of how much I can expect to lose is to consider that the exercise schedule I've proposed (20 minutes a day during the week, plus 60 minutes on the weekends) adds 3.2 times the amount of walking I've been doing. If I've been losing an average of 0.27 lbs per day since my water loss stabilized, then 0.27 x 3.2 = 0.864 lbs per day. If this holds true, then I can expect to arrive at my target weight of 190 lbs by December 28th. That's figured at 213 lbs - 190 lbs = 23 lbs to be lost divided by 0.864 lbs = 26.62037 days. So, my present weight loss from cutting my calories formerly supplied by grains, dairy and processed foods, added to the weight I'll be losing from increasing my exercise should get me to my target weight of 190 lbs by the end of the month. It's only 23 lbs to lose, so I don't see why not.