Q:A lot of diet plans are advertising on TV that they allow vacation from your diet days. What is the theory behind that, and is it a good idea?
Those diets are based on the very legitimate principle of carb cycling. The theory of carb cycling is based on the idea that we can maintain more muscle mass (the building block of metabolism) if we vary the amount of carbs from day to day.
Carb cycling is based on the control of glycogen levels. That is the form in which we store carbohydrates in our liver and muscles that are used are energy. As we go about daily activities, we either use those stores or store them as fat. By alternating how many carbohydrates we eat from day to day, the idea is that the stores are only replenished but are not saturated.
Carb cycling can be taken to the extreme though, thus interfering with attempts at weight loss. As everything in this program, ability to sustain things for a lifestyle is of the most importance. When you have diet days and free days, it is easy to take the free days too far, which stems from the feelings of deprivation on the diet days. Also, the foods that you eat on the free days can make it more difficult to get back on track as they can lead to residual cravings.
I think a more moderate approach is to alternate lower carbohydrate weeks with higher carbohydrate weeks. I see good success having clients alternate the Food Detox Plan (lower carb) with the Keep It Simple Plan (higher carb). The Keep It Simple Plan involves natural moderate-glycemic carbohydrates which can help to curb cravings without spiking blood sugar, causing fat storage, and causing rebound cravings.
In closing, having days when you eat more carbohydrates than others can have a positive impact. When employing this strategy, it is important to be aware of how your body responds and your own personal behavioral patterns. It is a strategy that can work well when employed with caution.