In my psychiatry practice many of my patients embrace a diet with low to no refined carbohydrates or processed foods and feel emotionally better within weeks. Some have not felt so mentally and physically well in decades.
Then the eating holidays (Halloween through New Years) arrive. Unless they are hermits they must confront social pressures to abandon good eating habits (Halloween treats, Grandma's traditional turkey stuffing, the neighbor's Christmas fudge, candy canes, New Years' banquets, holiday ads, less time to prepare healthy meals, etc.).
Most report they feel dreadful with their first high sugar and starch food mistake, but as they continue eating such foods they grow used to not feeling their best. By the time January arrives they have gained weight and slipped back into depression, with the daily mood swings every 2-3 hours that accompany a refined carbohydrate diet (see graph below).
From They Are What You Feed Them, by Dr. Alex Richardson
[A word on the graph above: When insulin rescues your body from slipping into a coma by taking excess blood sugar away it has to put it somewhere. So insulin helps convert blood sugar to fat and store it in fat cells for future use as fuel. But so long as insulin is high, stored fat cannot be released to use for fuel. Blood sugar drops, and hunger strikes again. People who eat high carbohydrate/low fat diets encounter this roller coaster effect throughout the day, suffering frequent hunger symptoms while gaining weight.--AC]
I start early to address this problem by documenting my patients' moods along with diet reports when they first undertake the low refined carbohydrate program. My notes tell me how well my patients felt when they ate one way v. eating according to unhealthy habits.
You can do this yourself by starting a dated/timed journal of foods and moods using the ABCs (Date, Time, Antecedents, or what prompted you to eat the food; Behavior, or what you ate, and Consequences, such as how you feel/what your glucometer says/etc. In a separate column record weight gain/loss over time). Journaling helps move eating habits from unconscious to conscious. It is also a way to get in touch with triggers for eating various types of food, and to solidify reasons to eat clean. Seeing the results of eating on and off target on paper helps make the process tangible for most people.
It's important to know that starch = sugar, and both sugar and starch promote addiction-like blood sugar curves that increase hunger and food cravings, along with moodiness (see graph above). Once on this roller coaster it's hard to get off.
One strategy set is to get with like-minded people for moral support over the eating holidays. Make healthy substitutes for your favorite holiday foods. When you go out to eat, don't be shy--ask for what you need. A large piece of lettuce can replace the traditional starchy hamburger bun, for example.
For my patients considering a reduction in carbohydrates close to the 'eating holidays' I encourage them to go slow, learn as much as they can about the process then embrace their new way of eating fully as a New Year's resolution.