Low carbohydrate (LC) diets have been around for decades and encompass a range of popular diet regimes such as Atkins, Protein Power and Zone. The many proponents of these diets would have us believe that carbohydrates (carbs) are some form of toxin which should be restricted or in some cases avoided completely if weight loss is to be attained. For years their claims have percolated on researchers, not to mention dieters and while these diets gain popularity through their burly claims and success stories, they often fail to demonstrate (convincingly!) any long term effects.
The past few decades have been enlightening in terms of scientific knowledge about low carb diets. However, despite a wealth of research in this topic area there remains much debate as to the efficacy of LC diets for safe and effective weight control. Here, I aim to allay the concerns that many people who seek to lose weight have about choosing a LC diet and provide information on whether or not a LC diet is necessary, sustainable and most importantly of all, safe.
THE PRO’S OF LOW CARB DIETING
IMPROVES HEALTH STATUS (1)
Recent short-term and long-term randomised control trials (deemed the gold standard of research) have demonstrated that a LC diet offers an attractive dietary option with regard to weight loss, glucose and insulin response, and important cardiovascular risk markers in both normal subjects and those with metabolic and other health-related disorders. What is more, makers of cardiovascular disease i.e. serum levels of triglycerides, high-density lipoprotein cholesterol (that’s the bad cholesterol to you and me) and hypertension are all improved with a LC diet when compared with a diet low in fat.
HELPS TO CONTROL INSULIN (2)
The specific mechanism underpinning LC nutrition to weight loss and chronic disease rests on the ‘master weight loss hormone’ insulin. Now, I won’t bore you by going into the ‘nitty gritty’ science behind the hormonal response of insulin to carb feeding but what I will tell you is that insulin is the KEY to weight control. What is important to note is that by consuming carbohydrate you increase insulin levels in your blood, which holds particularly true when foods with a high glycemic index are consumed i.e. chocolate, sweets, white bread, white rice etc. Insulin moves glucose (sugar) from the blood into the muscles and fat cells for storage after which insulin levels drop significantly. This can trigger hunger pangs and make you feel hungry when your body doesn’t require food. Frequent insulin spikes are also heavily associated with insulin resistance and the development of type II diabetes mellitus. To add further insult to injury, insulin inhibits fat metabolism which means that by consuming carbs before exercise you will be burning those carbs and not fat if exercising for less than an hour at a low-moderate intensity (...please do not consume a sports drink while walking on a treadmill!). If considering a LC diet, opt for low-GI carbs for a sustained energy release and to keep hunger pangs at bay.
REDUCE OUR APPETITE AND INCREASE OUR FEELINGS OF FULLNESS (3)
It is well established that certain food types may stimulate eating whereas others help with feelings of fullness (known also as satiety). For example, protein generally increases satiety to a greater extent than carbs or fat and may facilitate a reduction in energy consumption. By reducing carb intake it is likely that our protein intake will increase which offers one potential avenue through which a LC diet aids in weight loss. However, a life-long high protein diet can increase the likelihood of developing osteoporosis, a disease that leads to increased risk of fracture. Conversely, a diet too low in protein is also associated with osteoporosis. It is therefore important for you to be aware of your protein intake when on a LC diet.
THE CONS OF LOW CARB DIETING
ATHLETIC PERFORMANCE IS OFTEN COMPROMISED (4)
Carbohydrates are the main fuel source for training and recovery. Consequently, LC diets are not ideal for optimal performance, particularly in improving endurance exercise, ‘stop and go’ high intensity sports such as team and racquet games and high intensity events lasting 2-7 minutes. For example, during a football (soccer) match, liver and muscle glycogen (the storage form of carbohydrate) has been purported to decrease by up to 85%. Inadequate carb intake before, during and after a match will leave the body constantly fatigued.
Elite level athletes should follow a diet high in carbs in order to fuel their training and competition needs, allow for quick and efficient recovery and promote training adaptation Recreational and social athletes who are trying to lose weight would benefit from following a moderate carb approach to achieve their goals. Their carb requirements are usually much lower than elite level athletes so following a sensible eating plan that is low/moderate in fat and moderate in nutritious protein and carb is a good compromise for many athletes provided they include adequate carbs to match the intensity and volume of the exercise they participate in. Nonetheless, training in a LC state is a tactic often employed by sports teams and individuals in the off-season period when high training intensities (i.e. overload) are not the goal of the training period. In this instance, it would be worthwhile to consider taking a pre-workout supplement like Pulse V4 to offset some of the above mentioned performance issues. Pulse V4 contains a unique blend of performance boosting ingredients such as Caffeine, Creapure, AAKG, Beta Alanine, Citrulline Malate, Tyrosine, Taurine and Guarana which work synergistically to boost energy levels, increase focus and mental alertness, and delay the onset of fatigue; therefore enabling you to work harder, for longer in a low carb state. One specific ingredient that has taken the scientific world by storm in recent years is Beta Alanine with new scientific research being released regularly in support of its ability to increase muscular strength and power output and boost both muscular aerobic and anaerobic endurance. This can be taken alone or combined with other ingredients such as Pulse V4.
INCREASED RISK OF INFECTION (5)
When carb intake is low you are at a greater risk of infection. Inadequate intake of nutrients such as carbohydrate can compound the negative influence of heavy exertion (i.e. exercise, long shifts at work) on immunocompetence. Individuals wishing to partake in a LC diet may wish to supplement their diet with some immune boosting supplements such as vitamin C, vitamin A, echinacea, zinc and quercetin which may be effective in reducing infection risk. If fruit and vegetables are sparse in the diet, consider taking a multivitamin.
ASSOCIATED WITH INADEQUATE FIBRE INTAKE
Fibre helps your digestive system process food and absorb nutrients. It also helps lower blood cholesterol and maintain satiety. As carbohydrate foods like wholegrain breads and breakfast cereals and fruit are a good source of fibre, avoiding these foods can often mean you reduce your fibre intake to below recommended levels (the recommended intake of fibre for adults is 18g). To ensure adequate fibre intake the carbohydrates you eat should contain a source of fibre.
ASSOCIATED WITH INCREASED SATURATED FAT INTAKE
One persistent concern with LC diets is that the carbohydrate removed from the diet will be replaced with saturated fat. Eating a lot of saturated fat can increase the cholesterol in your blood. High levels of cholesterol are associated with a cluster or medical disorders such as heart attack, stroke and atherosclerosis (narrowed arteries). However, the demonization of saturated fat has been questioned in recent years. For example, a recent meta-analysis, which pooled data from 21 studies and included nearly 348,000 adults, found no difference in the risks of heart disease and stroke between people with the lowest and highest intakes of saturated fat (6). Interestingly, new research shows that replacement of carbs with saturated fat is, if anything, beneficial for risk reduction. The effect of saturated fat is reliant upon the constituents of the diet and, in particular, the effects of carbs on insulin that shift metabolism toward fat usage. However, more research is required to substantiate this claim.
NOT SUITABLE FOR SPECIFIC POPULATIONS
Reducing carb intake may not be appropriate for specific populations: patients with insulin-dependent diabetes, thyroid effects, ketotic hypoglycaemia of childhood, inborn errors of metabolism, corticosteroid, or growth hormone deficiency, certain elderly populations and individuals who consume excess amounts of alcohol or aspirin. These individuals are advised to consult a medical doctor prior to the engagement of a low carbohydrate dietary regime.
• LC diets have been associated with improvements in important health parameters such as cardiovascular disease and in assisting in the prevention of metabolic disorders i.e. type II diabetes mellitus.
• LC diets can help to reduce appetite and maintain satiety. These effects are most likely due to an increase in protein intake and a reduction in the intake of carbs with a high glycemic index i.e. sugary foods like chocolate, sweets, cakes, white bread etc. which, of course, are non-essential components of anyone’s diet.
• LC diets are associated with inadequate fibre intake and increased saturated fat intake - this can be problematic.
• Caution is warranted to athletes (both elite and recreational) when considering a LC diet.
• LC diets can increase risk of infection and compromise immunocompetence – particularly in the winter months.
• LC diets may not be suitable for specific populations.
1. Hite, A. H., & Berkowitz, V. G. (2011). Low-carbohydrate diet review: Shifting the paradigm. Nutrition in Clinical Practice, 26, 300-308.
2. Harrington, R. N. (2008). The role of sugar-sweetened beverage consumption in adolescent obesity: A Review of the Literature. The Journal of School Nursing, 24, 3-12.
3. Kushner, R, F., & Doerfler, B. (2008). Low-carbohydrate, high-protein Diets revisited. Current Opinion in Gastroenterology, 24, 198-203.
4. Ali, A., & Williams, C. (2009). Carbohydrate ingestion and soccer skill performance during prolonged intermittent exercise. Journal of Sports Sciences, 27, 1499-1508.
5. Walsh, N. P., Gleeson, M., Pyne, D. B., Nieman, D. C., Dhabhar, F. S., Shephard, R. J. et al. (2011). Position statement part two: Maintaining immune health. EIR, 17, 64-103.
6. Siri-Tarino, P. W., Sun Q., Hu, F. B., & Krauss, R. M. (2010). Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. The American Journal of Clinical Nutrition, 91, 535-546.