by D. Vogt

Created on: May 19, 2010

The 3 Day Tuna Diet is a variant of the popular 3 Day Diet, a crash diet intended to maximize weight loss over a short period (three days). The diet relies on essentially tricking the body into short-term starvation; it must be ceased after three days to prevent the body from adjusting by lowering its metabolism rate (and therefore reducing the rate of weight loss), but can then be resumed again for subsequent three-day periods. Like other fad diets, the 3 Day Tuna Diet often suffers from exaggerated expectations of its effects, but may be an effective if not ideal strategy for weight loss.

- How It Works -

The 3 Day Tuna Diet, according to WiseGeek.com and LoveToKnow.com, includes a specific dietary regimen for breakfast, lunch and supper over a three-day period. On the first day, breakfast consists of black coffee or water, half a grapefruit, and a slice of toast buttered with peanut butter. Lunch is a half-cup of tuna on a slice of toast, along with more black coffee, water, or tea. Dinner includes three ounces of meat, plus green beans, carrots, vanilla ice cream, one apple, and more of the same drink. The diet includes minor variations on the same theme for days 2 and 3.

Essentially this is a variant on the 3 Day Diet, also known as the Cleveland Clinic diet. Although not verified scientifically (and not actually from Cleveland), the diet's specification of a three-day regimen is not merely random. Drastic reductions in calories leads to weight loss, but after several days the body adjusts to a low-calorie diet by reducing its metabolism to a level more appropriate for what it mistakenly concludes is a famine situation. (This is because the human body was designed to function in conditions of food scarcity, not food abundance.) A three-day diet thus holds out the possibility of tricking the body, forcing it to burn additional calories but then returning to a normal calorie level before the body has time to lower the metabolism.

- Whether It Works -

There are several problems and warning signs associated with the 3 Day Diet and its variants, as explained in this Helium article. First, the focus on a specific and seemingly magical combination of ingredients obscures the real mechanism of weight loss, which is, barring some minor adjustments by special vitamins and minerals, still about increasing calorie expenditure through exercise and/or reducing calorie intake from food. In this sense the 3 Day Diet is a helpful suggestion for a low-calorie diet, but hardly the only group of foods capable of accomplishing the same results. Moreover, while "tricking" the body using short-term starvation regimens can be effective, it also leads to the psychological risk that dieters will "binge" during their off periods, meaning the diet in effect leads to weight gain.

Second, such diets also tend to exaggerate their short-term effects on weight loss. Advocates of the 3 Day Diet often claim that it will result in a loss of ten pounds. The 3 Day Tuna Diet in particular is not associated with such claims. However, in both cases, the actual loss of fat weight will be less extreme than the weight loss due to decreasing water levels. (In essence, restricting fluid intake causes dehydration, which is a form of weight loss but a particularly deadly and unsustainable one for obvious reasons.) This is another reason why the 3 Day Tuna Diet should not be adhered to for longer periods of time.

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