ALL YOU NEED TO KNOW ABOUT LOW-CARB DIETS
- January 27, 2016
In most diets, carbohydrates would be the highest macronutrient that’s consumed, followed by protein and fats. The major exception would be the recently popularized low-carb diets aimed at helping weight loss. Read on to find out how to make sure low-carb diets are healthy, discover their pros and cons, and figure out the best way to incorporate them into your lifestyle.
Keeping a Low-Carb Diet Healthy
When carbs are reduced from one’s diet, it’s important to gain calories from increased amounts of protein and fats instead – because the body still needs energy. If this doesn’t happen, and one consumes less than 1000 calories a day, issues like skin problems, weak nails and easily shed hair follow. That’s because the proteins that are needed by the skin, hair and nails are no longer available; the amino acids (building blocks of protein) have been used to provide energy.1 And that’s how increasing our protein intake in low-carb diets helps – we get enough for providing fuel, as well as building structures in the body. Simultaneously increasing the diet’s fat content is imperative as well, because fats, which will be used as energy, too, have some specific functions of their own (fuelling the brain, building cell structures, etc).2 When fats are used for energy in a low-carb diet, they’re converted into molecules called ‘ketone bodies’, which replace the glucose from carbs – this is the basis of the ketogenic diet. If reading this has got you wondering why carbs, then, need to be consumed at all, here’s the reason: the brain needs glucose in order to function. Ketone bodies can replace about 70% of the brain’s glucose requirement, but the remaining 30% will need to be fuelled by carbs. This can be delivered by consuming about 50-100g of carbs a day. 3 The Positives of a Low-Carb Diet The main advantage of low-carb diets is the fact that they help us lose weight. Weight loss – in itself – improves health factors such as blood pressure, blood cholesterol, triglycerides and the blood sugar response, regardless of which diet was used to lose the weight.4 Studies have shown that low-carb diets can also lead to these health improvements, even without any weight-loss. This is (probably) because these diets –
1] Lower Levels of Insulin
When our body converts carbs to glucose, a hormone called insulin, which enables our cells use the glucose for energy, is produced. When there’s too much insulin, however, our cells become resistant to it. Because insulin controls many other processes in the body, insulin-resistance leads to metabolic mayhem, eventually causing metabolic syndrome and type-II diabetes.
In low-carb diets, less glucose means our body produces less insulin, leading to a series of positive effects – making them work well for diabetics, too.
2] Increase Protein Intake
We know that low-carb diets typically involve high amounts of protein – this has its own list of health benefits. It promotes satiety in many ways, and even helps our body burn more calories in a day. You can read more about it here.2
3] Restrict Unhealthy Junk Food
Low-nutritive and fattening foods like sugary drinks, fruit juices, fried food, baked goods etc. are all forbidden in these diets. Their absence only helps the body in numerous ways.
4] Reduce Calorie Intake
Avoiding carbs reduces the variety of food we can eat (by cutting out the unhealthy ones), and may even make us consume less food; but, since the food is higher in fat and protein, it’s still filling and nutritious. The Negatives of a Low-Carb Diet The effects of a low-carb diet can be great – but it has its own set of drawbacks as well. Low-carb diets:
1] May Restrict Healthy Food, Too
Along with junk foods, low-carb diets also restrict foods that provide high-quality carbs, like wholegrains, legumes and fruits – which tend to be rich in various health-promoting compounds like vitamins, minerals, dietary fibre, and phytonutrients (healthy pigments from plants).
2] Aren’t Long-Term Friendly
In one study, people who followed a low-carb diet for more than 8 weeks ended up having a reduced stool weight. The diet also lowered the amount of some healthy fats produced by the friendly bacteria in our gut (probably due to inadequate fibre). Both of these factors may increase the risk for developing gastrointestinal disorders over the long-term.5
Also – diets high in protein (> 1.2 g/kg body weight per day) can affect the kidneys by creating too much acid and, as some studies have shown, increasing the risk of stones in the urinary track.
So anyone who follows a high-protein diet for a long period of time should consider having fruits and vegetables that are high in potassium (like bananas, green vegetables etc.), to fight the acidity. It’s also recommended that they monitor their kidney function from time to time.2, 6, 7
3] May Affect Physical Performance
Another potentially negative effect of low-carb diets is the depletion of the body’s stores of glycogen, the form in which glucose is stored in muscles. Since glucose is the primary energy source for exercising muscle, low glycogen stores can compromise an individual’s exercise performance- but this seems to be a temporary effect, which wears off in a few weeks, once the body has adjusted.4 It still may not be suitable for athletes or those prepping for an event (like a marathon), where physical performance is immediately required.
4] Are Difficult to Sustain
Studies have shown that low-carb diets are hard to stick to, and people may end up gaining back the weight eventually.8 So it is best to keep it as a short-term plan (ranging from weeks to months), and follow it up with a more sustainable long-term diet plan. Find out more through 5 evidence-based facts about weight loss.
So, how much carb should I eat?
Here’s how we classify the carbohydrate content of a diet:
|Type of Diet|| Amount of Carbohydrate|
(% of total calories)
|Moderately restricted carb diet|| 26%–44% of total calories|
|Low-carb diets|| 26%|
(which represents <130 g/d in a 2000 calorie diet)
Very low-carb diets
(20–50 g of carbohydrate, depending on total caloric intake)
You can also calculate how many calories come from carbs by looking up the grams of carbs in that food, and multiplying it by 4, (since each gram of carb provides 4 calories). Those who are trying to lose weight can try a low-carb diet, but (as we mentioned earlier), it’s probably wise to phase it out into something more sustainable. Those who have metabolic syndrome, prediabetes or are insulin resistant, can try a moderately restricted carb diet, as suggested by evidence. 4 For the rest, as long as you’re following a balanced diet that’s filled with healthy options, you’re already on the right track towards a healthy, happy lifestyle.
1. Finner AM. Dermatologic Clinics 2013, 31(1): 167-172.
2. Pesta DH, Samuel VT. Nutrition & Metabolism 2014, 11: 53.
3. White H, Venkatesh B. Critical Care 2011, 15(2): 219-219.
4. Liebman M. Nutrition 2014, 30(7): 748-754.
5. Brinkworth GD, et al. British Journal of Nutrition 2009, 101(10): 1493-1502.
6. Reddy ST, et al. Am J Kidney Dis 2002, 40(2): 265-274.
7. Robertson WG, et al. Clin Sci (Lond) 1979, 57(3): 285-288.
8. Curioni C, Lourenco P. International journal of obesity 2005, 29(10): 1168-1174.