Cutting it out?

Just how healthy are low-fat and low-carb diets?

You might have already tried every diet under the sun, and the chances are, you’ve learnt valuable lessons. Maybe you meticulously calorie counted every mouthful that passed your lips, only to lose half a stone and then begrudgingly watch it pile back on, or perhaps in the past you tried a meal-replacement plan only to find it left you foggy-headed and irritable. There are so many different diet fads that pop up, it can be a challenge to keep track of the good and the bad.

Low-fat and low-carb diets are two of the most popular kinds of eating plans but, if you give them a shot, will they help you to shape up for the long haul and set up healthy habits that you easily weave into your life? Before embarking on any new eating plan, it’s important to prepare yourself for what you might experience along the way in order to help you decide whether it’s the right fit for you, so we’ve done the groundwork for you.

THE LOWDOWN ON CARBS

Excess carbohydrates are often touted as one of the biggest weight-gain culprits. After you eat carbs, your body produces insulin to help transport glucose molecules (produced as a result of eating the macronutrient) into cells to produce energy. If there is excess carbohydrate in the body that can’t be used up or stored as muscle or liver glycogen, it will be stored as fat.

‘Sugar and ultra-processed starches put a very high glycaemic load on your body (the speed at which your body converts the food you eat into glucose). Starches, such as potatoes and grains, are simply long chains of sugar molecules that are very quickly broken down into glucose when you eat them. The more processed these starches are – as in the case, say, of flour or pure sugar – the

quicker that process happens and the higher the glycaemic load on the body,’ says Fran Mcelwaine, functional health practitioner at Real Health & Wellness (realhealthandwellness.com).

Insulin also suppresses your satiety hormone, leptin, which means you are more likely to over-eat. ‘Consuming high amounts of sugar or processed starch, therefore, leads to high levels of insulin in the blood, which then causes blood sugar to drop to lower levels than normal. This is when you experience cravings, which are a sure sign that your blood sugar has become dysfunctional to a greater or lesser degree,’ says Mcelwaine.

Carbohydrates from wholegrain products (such as brown rice) don’t cause the same blood-sugar ups and downs as processed ‘unhealthy’ carbs because these foods contain more fibre. Fibre is digested slowly, which leads to a reduction in blood sugar spikes and enables your body to extract beneficial nutrients from food. Fibrous wholegrains also help to keep you fuller for longer.

So, what’s the solution to getting your health in better shape?

Lowering your intake of carbohydrates will help regulate insulin sensitivity as your body is not required to produce as much insulin. ‘That’s why, often, removing most carbs from the diet works for weight loss. Some people opt for a ketogenic diet, for which you cut your carb intake to 30g a day, and this works for them. This is simply because not eating any carbs at all keeps blood sugar levels very low and steady,’ adds Mcelwaine. The ketogenic diet (low carb, high fat and moderate protein) helps trigger weight loss because, when you eliminate carbs, your body creates ketones (substances that break down fat for energy), meaning that you’re switching into fat-burning mode instead of the body’s fat-storing mode.

It’s not as easy as it sounds, however, because when you replace carbs with a higher intake of fat and protein, you may initially experience unpleasant side effects such as brain fog, fatigue, mood swings, nausea and muscle cramps. Plus, you may not have enough energy to fuel your workouts. There are different scientific opinions on whether a ketogenic diet is suitable when teamed with exercise. One study found that a keto diet improved fat burning and exercise performance, but there’s also evidence that combining a ketogenic diet with exercise could impede energy utilisation. The best thing to do is be guided by how you feel when training. If you experience adverse symptoms, lower the intensity

of your workout or take a break.

THE LOWDOWN ON FATS

‘Fats are an important part of any balanced diet’

A low-fat diet can be beneficial for health but it must be a well-planned eating regime in order to get positive results

– this is because low-fat foods are often more processed and high in sugar and carbs. Low-fat foods may also contain health-harming trans fats which can lead to weight gain and cravings. ‘Low-fat diets will help you lose weight in the short term but the weight will return as soon as you add fats back into your diet. They also do not resolve the problem regarding sugar addiction, insulin resistance and appetite dysregulation caused by a high-carb diet,’ shares Mcelwaine.

A study conducted earlier this year found that people on a low-fat, plant-based diet ate fewer daily calories yet had higher insulin and blood glucose levels, compared to when they ate a low-carb, animalbased diet. Participants on the low-fat diet ate 550 to 700 fewer calories daily than on the low-carb diet, yet reported no differences in hunger, satiety or enjoyment between the two diets.

Cutting back on full-fat diary products and red meat could also lead to deficiencies in micronutrients like calcium and iron. Fats are an important part of any balanced diet, there are essential fatty acids (called essential because we can only get them through diet) which are necessary for the synthesis of fat-soluble vitamins such as vitamins A, E and D. ‘Our brain cells, cell membranes, nerve fibres and hormones are all dependant on fats to function optimally,’ believes Mcelwaine.

Interestingly, a study in the Journal of the American College of Nutrition showed that following a low-fat vegan diet was, in fact, more effective for weight loss than the ever-popular Mediterranean diet. Participants following the Mediterranean diet didn’t lose any weight, but those following a low-fat vegan diet lost almost a stone, including an average of 7.5lbs of fat.

It’s thought that calorie reduction was the triggering factor for weight loss because the participants following the low-fat vegan diet naturally ate

500 fewer calories compared with when following the Mediterranean diet.

THE VERDICT

Restricting what you eat to lose weight is never a sustainable plan because, as soon as you hit that milestone, you inevitably pile the weight back on. Cutting out food groups can contribute to negative effects on physical and mental health. You’ll naturally crave what you miss and experience side effects like low mood and energy. Instead, adopt an 80:20 approach. This means eating well 80 per cent of the time and indulging the remaining

20 per cent. You won’t feel deprived, instead you’ll be nourishing your body from the inside-out.