That's Fit

A recent Japanese study, published in the Kobe Journal Medical Sciences and most recently highlighted in Fitness Rx magazine, confirms what we've known for quite some time: eating foods high in simple, fast-digesting carbs can cause you to pack on more fat. The difference this time around, however, is that this study provides an additional explanation for why this happens.

When you drink copious amounts of regular soda and chomp on white bread, you spike your blood glucose levels (also known as blood sugar). You may be familiar with this concept from your own knowledge base or from hearing of this process from someone who has diabetes. In response, your body produces a large amount of insulin in efforts to bring your blood glucose back down from orbit by moving the glucose out of the blood and into the cells (whereas a person with diabetes may have to use synthetic insulin -- administered either by shot or pump -- to make up for what their pancreas is not able to sufficiently do on its own in this regard). After this occurs, all excess glucose is stored for later use as fat in white adipose tissue.

What the Japanese study adds to this understanding is an additional fat-storing process in which insulin also plays a role. The researchers discovered that insulin also prevents the breakdown of fat. It does so by blocking the activity of adrenaline and hormone-sensitive lipase. So, not only does following a diet high in simple carbs cause insulin levels to spike (and, as stated in the previous paragraph, sometimes fail to move all glucose out of the blood and into the cells, leading to it being stored as fat), but it also causes insulin to block fat breakdown.

Note: Just remember that not all carbs are bad. Whole grains, fruits and vegetables, and nuts should still be a big part of your diet. It's the sugar found in soda, sweets, and enriched flour that will cause the aforementioned spikes in blood glucose and insulin.