Hi Doc, I hope you are well and soon fully recovered from your current injury.
I have been cutting lately at a very slow rate to maintain my strength, but I have been struggling a bit with how to calculate the amount of calories deficit a week. I started my cut almost five weeks ago (At more than 84kg), and I am now at 82 kg, with TTDE being 1700. To target the number 80kg, I aim to cut 1% body weight per week, which is 0.82kg. Mathematically, 0.82kg fat loss equals 6314 kcal, which is 902 kcal deficiency daily. I’m not quite sure if my calculation is right, but intuitively, my TTDE would be only 800kcal a day, and it sounds ridiculously wrong to me.
Could you please help me to explain how you managed to calculate the amount of energy deficit to reach the goal of X% body loss (say, 1%) a week? Thank you so much.
I don’t think that the 3500kCal/lb “rule” is well-supported. I also don’t think that following “1% weight loss per week” strictly is reasonable, as weight loss isn’t linear. Rather, I’d recommend eating a modest energy deficit, as evidenced by some weight loss every week or two, and then adjust energy intake down as needed to hit your goal. Weight loss stabilizes over a much longer time, e.g. you probably wouldn’t realize the full extent of weight loss from a given energy deficit until months later. If you’re losing right now, I’d just keep the same energy intake until it stops working.
What has been really bothering me is that I love to make things optimally measurable (my background is in Data Science/Stats). If those “3500kcal” or “less than 1% a week” are not a rule of thumb evidently supported, what would you think about the number of 200 to 300 kcal deficit per week, which many people on the Internet used when I did a quick search? Also, if there is no mathematical formula behind it, is it just a game of trial and error? And how would you optimise the number to choose to be in deficit to reach the goal in the shortest time but to prevent strength loss the most? Would it be then, again, trial and error?
Sorry for being too annoying, but I’m really obsessed with numbers and with making things measurable.
Thank you, Doc, for your time and patience.
Jin
I think a 200 to 300 Cal deficit is a fine, yet arbitrary, place to start. In reality, we can’t be sure it’s a deficit unless you go from maintaining weight to losing weight and nothing else changes. I think that’s a bit too controlled for real-world application. I’d rather just remove a few hundred Calories and see what happens.
There is no optimal number and relatively slow weight loss shouldn’t have any effect on strength gain provided your programming is on point.
If you need specific guidance, we do offer professional nutrition guidance.