For about the past few years I have been exercising and developing knowledge about different diets people use in order to gain/lose weight, gain more muscle, and get rid of fat. A popular thing among weightlifters is to bulk up and then cut weight (click here for information on bulking). I personally have strayed away from this diet since the cutting phase requires a person to maintain a low-carb diet or to cut out complex carbohydrates completely. When first reading this, I thought to myself that there’s no way that can be healthy since carbohydrates are human’s main source of energy. So, are low-carb diets bad for you?
Null Hypothesis: Low-Carb diets are not bad for you
Alternative: Low-carb diets are bad for you
After some research I found a study that compared low-carbohydrate, high protein, high fat diet to a low-calorie, high-carbohydrate, low fat diet. Researchers conducted this study by randomly assigning 63 obese men and women to either diet for to track which group lost more weigh over the span of one year. After six months the low-carb diet had lost a higher percentage of body weight than the other group, but the differences after one year were not statistically significant. Both diets had a significant decrease in diastolic blood pressure. People with high diastolic blood pressure are more likely to have problems with their memory and thinking skills than those with normal levels which is less than 120/80 mm Hg (less than 120 systolic AND less than 80 diastolic) for an adult age 20 or over. Also, the insulin response to an oral glucose load decreased in both.
Bottom Line: The low-carbohydrate diet produced a greater weight loss, which was approximately 4%. Also, the low-carb diet was associated with an improvement in risk factors, such as coronary heart disease. Adherence to the prescribed diets were low which may have been set back to the effectiveness of the study. Therefor larger studies should be conducted in order to get a better understanding of the long-term safety of each diet.
In another study done by the Philadelphia Veterans Affairs Medical Center, they performed a test similar to the one above. Some differences were that the two diet groups attended separate two-hour teaching sessions every week for a month straight. Which was then followed up by monthly one-hour sessions for five additional months which was led by experts in nutritional counseling. Subjects were also given handouts, instructional nutrition labels, and other useful information to help guide the. Also, the subjects on the low-card diet restricted their carbohydrate intake to 30 g per day or less. While the low-fat dieters were not provided instructions on restricting total fat intake, but they did receive instruction that went along with obesity-management headlines of National Heart, Lung, and Blood Institute.
Some other key notes:
- Subjects were at least 18 years old and had and had a bmi of at least 35
- There were 132 participants involved in the study
- Stratified randomization used to ensure that each group contained equal numbers of women, subjects with diabetes, and severely obese subjects (bmi greater than or equal to 40)
- Study was not blinded
- Many participants dropped out before the end of the study
After the study was completed, researchers found that triglyceride levels decreased in the low-carbohydrate group. Many studies suggest that lowering triglyceride levels has an overall cardiovascular benefit. Also, insulin sensitivity improved after following this diet.
The Bottom Line: The study revealed that low-carb diets can improve triglyceride levels and insulin sensitivity. Also, that confounding variables such as the high dropout rate could have greatly affected the results in this studies findings.
On the other hand. I found a few articles that claim low-carb diets can elicit the below side effects:
- Induction Flu
- Leg cramps
- Constipation
- Bad Breath
- Heart Palpitations
- Reduced Physical Performance
Sometimes people temporarily put themselves at risk when they abruptly/drastically cut cubs out their diet. A few short-term effects are headaches, bad breath, weakness, fatigue, constipation, and diarrhea. Consuming less than 20 grams of carbs per day can result in ketosis. The mayo clinic states that: Ketosis occurs when you don’t have enough sugar (glucose) for energy, so your body breaks down stored fat, causing ketones to build up in your body. This causes the above stated side effects such as nausea, headache, mental/physical fatigue and bad breath. Then in heavily restricted carbohydrate diets other effects come into play. For example: vitamin/mineral deficiencies, bone loss, and gastrointestinal disturbances (symptoms of stomach pain, heartburn, diarrhea, constipation, nausea and vomiting).
What’s the cause for these side effects?
http://www.nejm.org/doi/full/10.1056/NEJMoa022207
http://scoobysworkshop.com/bulking-and-cutting/
http://www.nejm.org/doi/full/10.1056/NEJMoa022637#t=article
http://authoritynutrition.com/10-things-dietitians-say-about-low-carb-diets/
http://www.news-medical.net/news/20090824/People-with-high-diastolic-blood-pressure-more-likely-to-have-cognitive-impairment.aspx
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Click to access content_69_849.pdf
http://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/low-carb-diet/art-20045831?pg=2