Your body uses carbohydrates as its main fuel source. Complex carbohydrates (starches) are broken down into simple sugars during digestion. They're then absorbed into your bloodstream, where they're known as blood sugar (glucose). In general, natural complex carbohydrates are digested more slowly and they have less effect on blood sugar. Natural complex carbohydrates provide bulk and serve other body functions beyond fuel.

"One of the primary places where you are going to see metabolic changes on any kind of diet is in your gastrointestinal tract -- and that can include a change in bowel habits often experienced as constipation," says Sondike, who is also credited with conducting the first published, randomized clinical trial on low-carb diets. The reason, Sondike tells WebMD, is that most folks get whatever fiber they consume from high-carb foods such as bread and pasta. Cut those foods out, and your fiber intake can drop dramatically, while the risk of constipation rises.
For decades we’ve been told that fat is detrimental to our health. Meanwhile low-fat “diet” products, often full of sugar, have flooded supermarket shelves. This has likely been a major mistake, that coincided with the start of the obesity epidemic. While this doesn’t prove causation, it’s clear the low-fat message didn’t prevent the obesity increase, and it is possible it contributed.
Low-carb diets may improve high-density lipoprotein (HDL) cholesterol and triglyceride values slightly more than do moderate-carb diets. That may be due not only to how many carbs you eat but also to the quality of your other food choices. Lean protein (fish, poultry, legumes), healthy fats (monounsaturated and polyunsaturated) and unprocessed carbs — such as whole grains, legumes, vegetables, fruits and low-fat dairy products — are generally healthier choices.
If you want to cut costs even more you can replace the avocado in the tuna salad (if you are not lucky enough to find avocados on sale) with more vegetables. A drizzle of some extra olive oil on the salad will compensate for the reduction of fat from the avocado. You can also substitute any of cheeses in the recipes for other types of cheese that you may find on sale.
There is extensive evidence for the benefit of the Mediterranean style low carb diet, including cutting your risk of heart disease and diabetes. It has even been found to reduce risk the risk of breast cancer, compared with those on a low-fat diet. Consuming extra virgin olive oil (the fresh squeezed juice of olives) seems to be particularly beneficial when it comes to cancer, perhaps because it contains compounds such as polyphenols which are known to be anti-inflammatory.
If you want to cut costs even more you can replace the avocado in the tuna salad (if you are not lucky enough to find avocados on sale) with more vegetables. A drizzle of some extra olive oil on the salad will compensate for the reduction of fat from the avocado. You can also substitute any of cheeses in the recipes for other types of cheese that you may find on sale. 
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