Healthy eating habits/The Low Carbohydrate Diet: Risks, Alternatives and Monitoring intake

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What is a Low Carbohydrate Diet?[edit]

Diets that replace carbohydrates with foods containing a higher percentage of fat or protein are referred to as Low-Carbohydrate Diets. An example of this is the Atkins diet. The Nutrient Reference Values adapted by the National Health and Medical Research Council recommend that carbohydrates should contribute between 45-65% of total energy for the day [1]. Low carbohydrate diets reduce this to approximately 20% [2]. The rationale behind the Low-Carbohydrate Diet is that once carbohydrate restriction has commenced and carbohydrate stores are exhausted, the body switches to fat metabolism to make energy. One of the products of fat metabolism is ketones, and an accumulation of ketones puts the body into a state of ketosis. This leads to a reduction in appetite and an overall effect of weight loss [3].

Risks of long-term low-carbohydrate dieting[edit]

Long-term carbohydrate restriction of between 20-60g/day can be detrimental to health [4]. Risks include:

  • A 12% reduction in thyroid hormones. Thyroid hormones control metabolism. A reduced metabolism results in rapid weight re-gain once carbohydrates are re-introduced [4].
  • Mood swings associated with a decreased availability of serotonin in the brain. Serotonin is responsible for elevating mood [5].
  • Feelings of light-headedness, and decreased concentration due to low blood sugar levels [6].
  • Bad breath due to ketone production [6].
  • Vitamin, mineral (e.g. calcium and iron) and fibre deficiencies. This may lead to constipation, fatigue, headaches and other health outcomes [7].
  • A higher risk of heart disease due to a higher saturated fat intake [8].

Why do we need carbohydrates?[edit]

In order for the cells of the body to produce energy to sustain life, glucose is needed. The main source of glucose is carbohydrate foods (breads, cereals, rice). Fat and protein are much less efficient energy sources because they must firstly be broken down into their various components before they can enter the energy production pathway [9].

Carbohydrates are important for:

  • Brain function. The brain requires 25% of the body’s glucose to function; therefore regular consumption of carbohydrates supports this and enables concentration to be maintained, which is important for studying [3].
  • Fibre content. Low Glycaemic Index (GI) foods (e.g. wholemeal bread, brown rice, oats) are high in fibre and therefore prevent constipation [10].
  • Weight stabilization. Low GI foods keep you feeling full for longer so appetite is regulated and snacking is reduced [11].
  • Improving performance during exercise. Having a light carbohydrate-based snack before exercising (e.g. a piece of toast with jam) can improve performance because glucose is the number one fuel during exercise [6].

What types of carbohydrates should we eat?[edit]

There are two types of carbohydrates: simple, and complex.

Simple carbohydrates[edit]

Of the three types of simple carbohydrates, also referred to as sugars, glucose is the most important. Both natural (fruits and vegetables) and processed foods (candy, chocolate, soft drink) contain simple carbohydrates. Processed foods containing added sugars without any other nutritional benefits are referred to as ‘empty calories’. These foods may also be ‘High GI' as they provide a quick burst of energy.[10].The Australian Dietary Guidelines recommends consuming these foods in small quantities and infrequently [12].

Complex carbohydrates[edit]

Complex carbohydrates come from foods including unrefined/unprocessed breads and cereals, as well as brown rice and quinoa. These foods contain long chains of glucose molecules, known as starch. They require more work by the body to digest. These foods are often 'Low GI' because they provide a more sustained release of energy, keeping you fuller for longer as well as containing essential nutrients such as fibre and B group vitamins including folate [13].

For more information regarding healthy carbohydrate product choices as well as information about other food groups, please visit: [ http://www.eatforhealth.gov.au/food-essentials ]

The CSIRO Total Wellbeing Diet (TWD)[edit]

File:Image 1.1. Sample meal plan.png
Image 1.1. Sample meal plan with moderate level of carbohydrate

The associated risks of a low carbohydrate intake can be avoided if a moderate amount of carbohydrate is consumed. The TWD has been formulated to include 115g of carbohydrate per day Invalid <ref> tag; invalid names, e.g. too many. This is less than the 250-300g suggested by the NRVs, but is more likely to be followed in the long term than the 20-60g recommended in low-carbohydrate diets [1]. The TWD suggests eating Low GI carbohydrate containing foods equal to:

  • 1 cup of cereal and
  • 2 pieces of wholemeal bread,each day.

For more information on the TWD, including ‘Free Foods’ that can be used as snack items (i.e. negligible carbohydrate content), visit:

[ http://www.csiro.au/Outcomes/Health-and-Wellbeing/Prevention/Total-Wellbeing-Diet.aspx ]

Counting carbs – How to?[edit]

The EasyDietDiary is a mobile phone application that allows you to track how much carbohydrate you are eating, and can help you stay within the limits of total carbohydrate intake for the as day specified by the TWD. There is the choice of over 45000 different foods as well as a function to create your own recipes.

For more information regarding carbohydrate tracking, please visit: [ http://easydietdiary.com/ ]

References[edit]

  1. a b Stewart R. (2012). "Griffith Handbook of Clinical Nutrition and Dietetics", Griffith University, School of Public Health: Australian Publishing
  2. [1], O’Neill M. (2006). "CSIRO Total Wellbeing Diet Review". Retrieved from http://www.smartshape.com.au/a/680.html
  3. a b Silverthorn DU. (2010). "Human Physiology: An Integrated Approach", Pearson Benjamin Cummings
  4. a b [2], Sears B. (2012). "Harvard explains why people regain weight with the Atkins diet". Retrieved from http://www.zonediet.com/blog/2012/10/927/
  5. [3], Benton D. (2002). Carbohydrate ingestion, blood glucose and mood. "Neuroscience & Biobehavioural Reviews". "26", 293-308. Retrieved from http://0www.sciencedirect.com.alpha2.latrobe.edu.au/science/article/pii/S0149763402000040
  6. a b c [4], Crowe TC. (2003). Low Carb Diets: Potential Short and Long-term Health Implications. "Asia Pacific Journal of Clinical Nutrition". "12", 397-403. Retrieved from http://www.atkinsexposed.org/atkins/133/
  7. [5], Mooney E, Farley H, & Strugnell C. (2004). Dieting among adolescent females – some emerging trends. "International Journal of Consumer Studies", "28", 347-354. Retrieved from http://onlinelibrary.wiley.com/doi/10.1111/j.1470-6431.2004.00392.x/full
  8. [6], Hosmer C. Low-Carb, High-Protein Diets. "Harvard Health Publications. Harvard Commentaries on Health". Retrieved from http://0search.proquest.com.alpha2.latrobe.edu.au/docview/1370166554
  9. Sadava D., Heller C., Orians G., Purves W., & Hillis D. (2008)"Life: The Science of Biology". Sinauer Associates
  10. a b Whitney, E., Rolfes, S. R., Crowe, T, Cameron-Smith, D. & Walsh. (2008) Understanding Nutrition, South Melbourne: Cengage learning Australia Invalid <ref> tag; name "understanding nutrition" defined multiple times with different content
  11. [7], Flatt JP. (2009). Importance of nutrient balance in body weight regulation. "Diabetes Metabolism Research and Reviews", "4", 571-581. Retrieved from http://onlinelibrary.wiley.com/doi/10.1002/dmr.5610040603/pdf
  12. [8] NHMRC. (2013). Eat For Health: Australian Dietary Guidelines. Summary. Retrieved from http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n55a_australian_dietary_guidelines_summary_131014.pdf
  13. Longe J. (2008). Carbohydrates. The Gale Encyclopedia of Diets: A Guide to Health and Nutrition. Cengage Learning Australia.