I've revised it to do the following:
- Calculate caloric needs based on either total body weight or lean body mass by providing the ability to enter body fat percentage. This gives a much more accurate result for heavy people whose extra weight is largely contributed by fat which doesn't require much protein to sustain it.
- Provide the ability to specify how much fat-related weight you'd like to lose each week. The calculator will also flag unrealistic weight loss goals including those that would require cutting protein down to unhealthy levels.
- Allow any carbohydrate intake level to be entered. If the carbohydrates entered exceed 120 grams a day, the calculator changes its recommendation of fat and protein levels to match the nutrient intakes that appear to be the healthiest, based on the research I reviewed for my new book.
The calculator continues to account for the additional protein required by people on very low carb, ketogenic diets. But it also makes it clear that as carbs rise and the diet continues past the first few weeks when the body adjusts to the ketogenic state many people will need far less protein than they might think. Cutting out that excess protein is often the easiest way to break a low carb weight loss stall--and to eliminate diet-associated dragon breath.
I found that when I calculated my own caloric needs by entering my body fat percentage as measured by my Tanita scale first thing in the morning, the calorie and protein levels that the calculator came up with matched exactly the caloric intake and protein levels my food logging had shown to lead to continuing weight loss and, when I reached goal, successful maintenance.
This had not been the case when I calculated my nutritional needs using other online calculators that asked only for my total body weight. Most interestingly, entering my body fat percentage along with my total body weight into the new calculator provided a new daily calorie level that was a couple hundred calories higher than that provided by other calculators.
This eliminated the caloric difference that in the past I had attributed to the "metabolic advantage" of a ketogenic diet. It turns out that the only reason I could lose weight on a ketogenic diet at a higher caloric intake than suggested by the formulas beloved by nutritionists is that I have more lean body mass for my size than their whole-body based formulas assumed so I burn more calories.
This is in line with much of what I learned doing my research. I'd love to hear from you as to how the calculator's estimates match your own experience maintaining your current weight or achieving weight loss. Post in the comments section of this post and we'll keep the discussion going there.