Diets have been around for decades upon decades and have helped many people lose weight or just maintain a healthy lifestyle.When most people look for a diet to go on, they follow what are known as fad diets. Fad diets are diets that are popular for a period of time and seem to promote unreasonable fast weight loss or unsensible health benefits. When asking certified nutritionists or dieticians, many of them reject the ideals of these fad diets and encourage a healthy diet that doesn’t require you to count calories, eat no carbohydrates, or starve yourself. But some people are determined to believe that fad diets work due to the metabolic processes on the cellular level, like cellular respiration and ATP production.
Cellular respiration uses ADP, a phosphate group, and energy to produce ATP and a water molecule. The question is, where do you get energy from out of nowhere? Food molecules are made up of chemical bonds that hold chemical energy, which can be used in cellular respiration. Specifically glucose holds a lot of chemical energy and is the main source of energy to drive ATP synthesis.
Aerobic respiration, a kind of cellular respiration that requires oxygen, goes through steps including glycolysis, which breaks down the glucose molecule into pyruvate. From there, pyruvate is broken down to form acetyl-CoA. The acetyl-CoA is useful for the next step of the Krebs Cycle, which produces carbon dioxide, NADH, GTP, and FADH2. All of these components are used in the electron transport chain, which takes place in the inner membrane of the mitochondria. In all, aerobic respiration produces 30-32 molecules of ATP from one molecule of glucose. This process of cellular respiration yields a great amount of energy but is not the most efficient way and can be used when doing low-intensity or everyday activities.
Another, more efficient, cellular respiration process, called anaerobic respiration, doesn’t require oxygen to function. Human muscles do not need oxygen to respire and produce a net amount of 2 ATP molecules. If an intense exercise requires more oxygen than already supplied, your body will start to use pyruvate instead. The glycolysis process does not require oxygen to function and can provide pyruvate when oxygen levels are low in order to drive muscle contraction. The anaerobic respiration process is faster than aerobic respiration because only a net amount of 2 ATP molecules are given off per glucose molecule, spending less time producing energy. Doing an exercise for 1-3 intensely makes your body rely on anaerobic respiration in order to create ATP.
When the body is low on glucose to fuel cellular respiration, your body will go to its next resource, fat. Fat molecules, called triglycerides, are broken down into fatty acids by a process called lipolysis. From there, the fatty acids are oxidized into acetyl-CoA. That acetyl-CoA from the triglyceride molecule is used in the Krebs Cycle instead of the acetyl-CoA derived from glucose. The fatty acid molecules produce over 100 ATP molecules per fatty acid molecule, which is almost 4 times as much as glucose molecules would produce.
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Intermittent fasting has become one of the leading diets fads. There are different variations and intensity levels to this diet depending on how long you decide to fast. The most common fast is 16:8, where you fast for 16 hours straight and only have a 8 hour eating window. The reason why many choose this diet is due to the fact that there are not any food restrictions required to see results.
The reason why fasting creates weight loss is due to the use of fat molecules to fuel ATP synthesis. When you stop intaking food, your body will run low on glucose and resort to fat molecules. This means that your body will burn fat as you fast. There is also evidence that intermittent fasting helps improve cholesterol, blood sugar levels, and blood pressure. Doesn’t sound so bad, right?
As you become familiar with your ATP synthesis and diet fads knowledge, you see that there is a connection between the two. Diet fads can be a useful way to burn fat if done correctly and with commitment, but many people recommend exercise to see faster results. So when you are in the lookout for a new diet to try, look up the science behind it all and see which one fits into your lifestyle the best.