Long, long ago, in the olden days, like when I was a child, meals were specific events at specific times. Our mothers capably produced three squares a day, and at night, when the last dish was done, they rested. The evening fast is the reason we have the word "breakfast": in theory, in the morning, after a good night's sleep, we break our fast and take in the calories we are going to burn during the day's work.

Nowadays, the family meal is a rarity, and our eating habits are more fluid. The revolution of the 24-hour society has happened gradually but steadily. We work crazy hours, we sleep crazy hours, we shop crazy hours, we stay online for very crazy hours, and consequently, we eat at all crazy hours. The 24-hour eating cycle, however, has not been kind to our waistlines. One-third of Americans are obese, and another third are overweight. The U.S. Centers for Disease Control & Prevention projects that 42 percent of all Americans will be obese by 2030. The future of America is looking neither sleek nor fit.

It is possible, however, that a mouse will save us from a chubby fate. It turns out that, genetically, mice and humans are quite similar, as fewer than 1 percent of the genes in question are unique to either species. Much of what we know about human disease has come from studying mice. Comparing the genetic blueprint of another mammal to that of humans helps scientists figure out what really matters in the human genome, and what is just filler.So when mice in a study do something dramatic like losing weight, the humans crunching the numbers perk up and notice.

In one particular study done at the Salk Institute in La Jolla and published in May, two groups of mice ate the same high-fat, high-calorie diet for 100 days. The only difference was that one group was allowed to eat whenever they felt like it -- 24/7, as the young people say -- while the other group was restricted to doing all of their eating in an eight-hour period, followed by a fast of 16 hours. In other words, they didn't eat at night. At the conclusion of the study, the mice that fasted overnight, in spite of their ample diet, were reasonably lean and fit, while the constant grazers were obese, with health issues like high blood sugar, high cholesterol, liver disease, and problems with their metabolism. In other words, like an awful lot of Americans.

I have actually conducted this study informally at home, except that at the time I did it, I called it "Lent." One Lent several years ago, I gave up eating anything at all after dinner, especially that luxurious bowl of ice cream or bag of peanut M&Ms that went so well with nighttime television. Although my intention had been more spiritual than dietetic, I noticed that by Easter, I had lost weight and size, and felt pretty healthy. Then, during the rest of the year, I forgot about this important lesson. I went back to my indulgent evenings, and my clothes gradually got tighter. I can vouch for the mice that fasted, because when I stopped eating for the day after an early dinner, I saw and felt a difference.

So, after reading about this study, I went back to the Lenten program. If mice can do it, so can I! The daily fast is a good experiment to try at home because it's easy, it's free, and it's reversible. And unlike some fad diets, it can't hurt.

I can again report that the results are encouraging. My daily fast is a 12-hour food-free zone, rather than the mice's 16-hour one. If I eat breakfast at 6 in the morning, I make sure I finish dinner by 6 in the evening. This gives my digestive system a much-needed rest from its daily work: the mouse study found that the liver especially seems to need some down time from the digestive process in order to avoid metabolic exhaustion. I definitely fall off the wagon, like when I visit my daughters who live in cities with fantastic restaurants, or go to a late movie and just have to get a small popcorn. Mostly, though, if I live the mouse way, I can eat what I want within that 12-hour window without feeling deprived, and stay in reasonably good shape. Although we vegetarians generally eat low on the food chain, I am finding that when I eat is as important as what I eat.

Unscientific conclusions:

A: The mice are right.

B: Not eating at night may seem fashionably retro, but like most of the stuff our moms told us when we were kids, it's also good for us.

These are the opinions of Valerie Schultz, not necessarily those of The Californian. Email her at vschultz22@gmail.com.