Richard Carlson, Ph.D., writes self-help books. When his fourth, You Can Feel Good Again, was being prepared for foreign publication, the publishing company asked Carlson to get an endorsement from Dr. Wayne Dyer, a self-help author who had written a number of bestsellers.

Carlson was hesitant because Dyer had already endorsed another book of his. He sent out the request anyway, didn't get a response, and relayed that to the publisher.

So imagine Carlson's surprise, embarrassment, and fear when the book came out and contained Dyer's old endorsement. Such a breach of literary etiquette could not only create ill will but also a lawsuit.

So Carlson wrote Dyer an apology, emphasizing that his literary agent had already demanded that the publisher recall the books.

Dyer wrote back and said it was unnecessary to pull the books from the shelves. He added in the note that "There are two rules for living in harmony. #1) Don't sweat the small stuff and #2) It's all small stuff."

As a philosophy for life, Dyer's observation which became the title of Carlson's sixth book works.

As a way of looking at your diet, however, it doesn't. If you want your diet to really work, you need to sweat the seemingly small stuff.

Why? Because when the small stuff builds up so does your gut and butt.

Not so long ago, I asked my father to buy the three 32-ounce containers of the plain Great Value Greek NonFat Yogurt that I normally purchase each week when he went to Walmart. He didn't check the label closely, however, and bought the vanilla flavored yogurt instead.

I promptly returned it.

I could tell this bothered him. I could tell he thought I was going overboard with what he used to call "this healthy eating stuff." But when it comes to what I put in my body, I dismiss the advice of Dyer and Carlson and sweat the small stuff.

That's because one cup of the aforementioned vanilla-flavored yogurt contains 180 calories, 27 grams of sugar, and 19 grams of protein, yet one cup of the plain contains 120 calories, nine grams of sugar, and 23 grams of protein.

Over the course of the week and consumption of the three containers, eating the mistake would've meant consuming an additional 720 calories. If I make a "small" mistake like that each week, one year later I'm 10.7 pounds heavier.

Another reason that I sweated the small stuff and returned the purchase was that the additional calories are absolutely the worst kind: added sugars.

There is only one ingredient listed on the label of the plain yogurt: cultured pasteurized Grade A nonfat milk. The vanilla version begins that way and then sugar and fructose follow.

So eating the mistake would've not only meant consuming more total calories but also an extra 216 grams of added sugar. If I make a mistake like that each week, one year later I've ingested 24.6 pounds of added sugars.

Carlson writes to begin his book that "Often we allow ourselves to get all worked up about things that, upon closer examination, aren't really that big a deal. We focus on little problems and concerns and blow them out of proportion."

Gaining 10.7 pounds in a year by eating 24.6 pounds of added sugars is clearly not a little problem. The only thing getting blown out of proportion in this case would be your belly and backside.

And that's happening in the U.S. When the nation was broken down county by county by researchers at the University of Washington's Institute for Health Metrics and Evaluation, they discovered that in more than 67 percent of them physical activity increased from 2001 to 2009. Yet somehow obesity rates for men or women declined in just nine.

If exercise is up, shouldn't obesity be down?

Not if the nation doesn't sweat the "small stuff" with losing weight.

Like counting calories.

Last May, BMJ published research conducted in New England by Harvard University that showed the typical adult order at a fast food restaurant was 836 calories, yet the subjects' estimates of cals consumed was 175 calories lower.

If you make that mistake at only one of your three main meals each day for a year surprise, surprise you're more than 18 pounds heavier.

But unwanted weight gain, doesn't always have to be a surprise. It can be a conscious decision.

Take your selection of 100 percent whole wheat bread, for instance.

The brand I use contains 50 calories per slice, but 70 or 80 calories per slice is more typical.

If I eat a loaf a week (and I will more during weeks where I ride so many miles that I need extra carbohydrates), my choice saves me 660 calories when compared to the higher number of the two other options.

In short, when it comes to weight maintenance, weight loss, and even weight gain, your degree of success is determined by your attention to detail. So put Carlson's self-help book away temporarily, sweat the small stuff, and you'll make progress.