There are a growing number of people out there who will argue that as long as the food you are consuming fits the calorie amount you wish to consume and the macro profile, the number of carbs, proteins and fats you consume per day, then it is fine to it that food.  Therefore it is entire possible to get a six-pack consuming one Mars bar per day. 

There are two problems with this line of thinking. The first is that engineered foods like Mars Bars are designed to make you crave more engineered foods, because the combinations of fats and sugars, or foods that taste like they have so many fats and sugars, is so rare in nature it makes you want more and more.  It is almost like a gateway effect; will one Mars Bar do?  What about one bag or crisps or one doughnut?  Some people do have the discipline, but many don’t. 

The second point here is that the Mars Bar significantly limits your calorie options. A Mars Bar is around 230 calories. For most people following a diet they will be eating around 1500-1800 calories a day, that’s twelve to fifteen percent of your daily intake!

This, linked to the fact that they are nutritionally of low value, means quite often that they don’t satiate all your needs. This is why they are seen as empty calories.  So by consuming that Mars Bar you have not only reduced the calories you have available for other, better, food options, you have also created a situation where your body still craves food, as the nutrient requirements you have haven’t been filled.  This is why you can often see people overeat in fast food places, because the nutrient content of the food they are buy is so low it doesn’t satisfy you fully. 

It is also worth considering the simple mentality that comes into play here.  Creating an environment where you are trying to lose weight and make good choices, but still indulge in something on a daily basis in the early stages isn’t an ideal basis for successful results.  Early on you want something achievable that allows for occasional indulgences, but not on a daily basis. 

So yes the science is correct, you can consume a Mars Bar a day and lose weight achieve your goals, but if you truly are serious about making the changes you want to get the results you want, then why would you want to?