What it is: The Whole30 is not a weight loss diet, but a healthful eating plan based on a book, “It Starts With Food,” by Dallas and Melissa Hartwig. The authors espouse eating, for 30 days, single-ingredient, non-processed food and eliminating food and drink that can cause insulin jumps or digestive trouble. They write in depth about the science of nutrition, the importance of hormones and why typical low-fat diets fail to promote weight loss and good health.

How you do it: Don’t count calories. Focus on what you can eat. Ask if a food is making you healthier. Those were the pieces of advice I clung to as I embarked on this month of hel — I mean, this Odyssey. I planned my meals in advance that first week, shopping the edges of the grocery store where the fresh food is stocked. Meat, fish and fowl were permitted, as were any fruits, vegetables, nuts, seeds and healthy fats like olive and coconut oil. Off limits: added sugar; alcohol; grains, legumes and dairy.

What? Had I really committed to no cheese and no cream in my coffee? I had. I joined a Facebook support group of others undertaking the challenge, agreeing to check in with a “like” for each day of success.

What happened: The first two weeks of the challenge, I was groggier than usual. But to my surprise, I was able to easily resist the office treat table because I simply didn’t feel hungry all day. I was eating hearty meals that kept me full for hours: eggs and veggies for breakfast, big salads with vinaigrette dressing for lunch and meat-veggie-potato dinners with fruit for dessert. I snacked on cashews or almonds when I coudn’t make it between meals.

By the third week I was sleeping soundly all night, surely a result of giving up my daily glass of red wine. I also noticed that when I ate enough, and particularly when I included enough fats, I had more energy for my (admittedly modest) workouts. By Week 4, my clothes felt a little looser. By the end of the challenge, I had lost 6 pounds and was feeling fine.

Can it last? Finding a way to sustain the diet, with occasional modifications, was a hot topic among those on the Facebook support group. Most of us lost between 6 and 15 pounds in the month and agreed this way of eating was easier than we anticipated. But we also knew we wanted to eat sweets or have a beer from time to time.

The Hartwigs suggest that after the 30 days, you slowly reintroduce foods from the categories you’ve eliminated. If you can eat them with no ill effects to your digestion, sleep or appetite, that’s good news. If you suffer, consider eliminating the food again. They make a strong case for having added sugar and alcohol be only very occasional treats.