A middle-aged, 140-pound woman who works out hard for 60 minutes four times a week and has a surprising amount of muscle because of it needs to consume at least 2000 calories a day to maintain her present weight — and that hard-earned muscle. Yet according to the current government recommendation, she should consume about 50 grams of protein a day.

That’s about 10 percent of her daily calories, a percentage I have found to be far too low if she wants to maintain that muscle mass, something that is oh-so important for both women and men at any age.

So how many grams per day should this middle-aged, 140-pound woman be consuming? That depends on a number of things, which is why I could not conclude last week’s column in good conscience simply by regurgitating the government’s one-size-fits-all ratio.

But is that the right question to address today? After all, there’s a good chance you’re not middle-aged, a better one that you’re not 140 pounds, and a 50-50 chance you’re not female.

So let’s start by establishing that a number of experts believe that while the government recommendation keeps you from becoming protein deficient, a higher percentage is needed — about 50 percent more or 75 grams per day for that 140-pound woman who works out — to enhance health.

Yet I have found that doubling the suggested increase, so that the protein accounts for at least 30 percent of the day’s calories works really helps most of the people who consult with me. In fact, I only go as low as 30 percent on the days I ride for three hours or more on the bicycle.

On days when I ride for an hour for recovery or lift weights to maintain muscle mass, between 40 and 45 percent of my calories come from protein.

If you’re puzzled at how a lacto-ovo vegetarian can pound down so much protein, I do so by eating the following items in abundance: egg whites, soy-based meat substitutes, fat-free Greek yogurt, fat-free cottage cheese, fat-free mozzarella cheese, cup cheese, and two different protein powders.

Consuming so much protein allows for the muscles damaged during the long rides and weightlifting to be repaired and — if I do things just right at my age — grow. But there’s a secondary benefit that probably interests the typical adult far more.

When you eat a higher percentage of protein, you can eat more. Significantly more.

When you eat what typical Americans do, the digesting, absorbing, transporting, burning, and storing of food requires about 10 percent of the calories consumed. In other words, eat 2000 calories and 200 of them get used to process the other 1800.

But this processing does not occur nearly as easily with the protein in food as with the fats and carbohydrates.

Research performed at the University of Lausanne in Switzerland and published in the September 2002 issue of Journal of Obesity found that the body wastes, so to speak, between 6 and 8 percent of carbohydrates to digest carbohydrates, about 2 or 3 percent of fats to digest fats, and between 25 and 30 percent of protein to digest protein.

As a result, Will Brink, a former athletic trainer who has written dozens of sports-performance articles and three books, says on a video available at his website that it’s “damn near impossible” to put on excess weight by eating excess protein. Brink said that in response to a study published in the Journal of the International Society of Sports Nutrition.

The study used 30 weightlifters in their 20s. Half, the control group, was instructed to eat and lift as they had been. The other half was told to do the same, but to make one dietary modification.

While they were to consume the same amount of fat and carbohydrates as they had prior to the experiment, they were to increase their consumption of protein to 4.4 grams per kilogram of bodyweight — 5.5 times the United States Recommended Daily Allowance.

For the next eight weeks the high-protein group averaged 307 grams of protein (1228 calories) a day. The control group averaged 138 grams (552 calories). Training volume, food intake, and body composition were monitored in both groups.

After eight weeks of consuming nearly 700 extra calories of protein a day, the researchers found that the increase in protein did not create additional body fat.

Studies such as this one are why I ended last week’s column by suggesting that determining the optimal amount of protein to ingest each day is a bit more involved than following a formula.

What I will suggest you do is what I have suggested so many times in the past: experiment. The composition of your muscle mass, your level of activity, and the way your body processes calories all influence what is the optimal amount of protein for you to ingest during the day.

There is, however, one bit of advice I can give about your early experimentation: When in doubt, eat more protein.