The Battle of the Diets: Low-Carb vs. Low-Fat

There are so many diets out there that it’s hard to keep up with which one is the latest. But there are some that seem to stick around and are compared to each other all the time.

Food pyramid

That’s right, I’m talking about the Low-Carb vs. Low-Fat diet that everyone seems to be going on about, especially since a new study was released.

Cutting down on certain foods will reduce the calorie intake and is bound to help you loose a few extra pounds. However, what is best for your body? What are the benefits and the drawbacks? Here we will investigate the two famous diets and look at the facts.

Low-Carb Diet

Diets can be easily incorporated into everyday life and this one is no exception, with some people even claiming that it is the easiest to do. People with diabetes often use it as it helps to control blood sugar better than other diets. Carbohydrates are one of the fundamental influences on blood sugar levels.

Moderate levels of carbohydrates are considered to be between 130 to 225g, low levels are under 130g and very low levels are considered to be under 30g. Carbohydrates provide energy to fuel the body, they’re broken down into glucose, so when consumed they increase blood sugar levels. There are two basic groups of carbohydrates.

Simple Carbohydrates

These are typically one-sugar molecules or two-sugar molecules. It includes refined carbohydrates, which are rapidly digested and release sugar quickly into the bloodstream. They are good for when you need a readily available source of energy, for example, before or during a workout. It is prone to energy highs and lows if eaten too regularly though so be careful or you could find yourself feeling worse off. The foods included in this group are white bread, honey, pastries and biscuits.

Complex Carbohydrates

These type of carbohydrates are made up of simple sugars joined together by bonds – the more bonds, the more complex and the longer it takes to break the carbs down. They reduce the chances of feeling fatigued or hungry between meals. Food that has undergone the least processing are the best such as wholegrains, jumbo oats, brown rise, spelt, rye and barley. These types of carbohydrates should make up the bulk of your carbohydrate consumption; they are the best source of nutrients and fibre. Good news for our bodies.


If you are cutting out carbohydrates you need some way of getting fibre into your system. Fructose is the natural sugar found in fruit and vegetable, which is considered to be a simple sugar. The high fibre content means the body digests whole fruit and veg more slowly than something that contains no fibre, but lots of sugar. These high fibre foods have less of a dramatic effect on blood sugar levels.

Side Effects

Of course, by cutting out any food group you are going to feel some side effects as your body gets used to the changes. You can experience symptoms of low blood sugar if you reduce the carbohydrates significantly. Symptoms include:

  • Sweating
  • Feeling shaky or weak
  • Extreme hunger
  • Slight Nausea
  • Dizziness
  • Headaches
  • Blurred Vision
  • Fast Heartbeat
  • Feeling anxious

You can gain a nutrition deficiency by cutting out certain foods, but you can battle this by adding in fresh fruit and vegetables that will help. Another side effect could be constipation from not having enough fibre in your system.

As there are a lot of calories in carbohydrates, cutting them out could reduce energy levels. To make up for the lack of calories you can eat more protein or fat. If you choose fat make sure that it contains fats such as nuts, avocados and olive oil (Monosaturated fats) and fish oils (polyunsaturated fats). However, having more protein can place an additional load on the kidneys and could lead to problems with bone-health.

You should always discuss any dietary changes with your GP before you start, so you know the risks that any diet entails.

Low-Fat Diet

Fat is a necessity that is needed to absorb fat soluble nutrients, manufacture cell walls and produces hormones. It is a source of energy and provides the body with fatty acids that it cannot make.

Eating the good kind of fats can protect you from heart and circulatory problems. There are three types of fat; saturate, monounsaturated and polyunsaturated fats.

Most people choose to do a low-fat diet to reduce calorie intake and improve cholesterol levels.

Saturated Fats

They are often linked with cardiovascular disease and high cholesterol. Foods that are high in saturated fats are red meat, cheese, burgers, butter and sausages, as well as coconut and palm oils. This type of food increase your risk of obesity, heart disease, type 2 diabetes and stroke. Cheese is not thought to be as harmful as it used to be.

Monounsaturated Fats

These are often found in olive, groundnut and rapeseed oils and nuts (almonds, cashews, hazelnuts, peanuts and pistachios), olives and avocados are good for heart health. They can help lower the harmful LDL cholesterol.

Polyunsaturated Fats

Found in corn oil, sunflower oil, nuts and seeds (walnuts, pine nuts, sesame seeds and sunflower seeds). There are two types of polyunsaturated fats; omega 3 and omega 6. They are essential fats that cannot be made in the body and are obtained from foods we eat. They prevent arteries from becoming blocked and may lower blood pressure. It is suggested that you eat 1-2 servings of oily fish per week to gain omega 3, or if you need an alternative you can get it from vegetable sources such as nuts or in the form of a supplement, but always talk to your GP first.

What it entails

A low fat diet will include foods such as whole grain food version, lean meats, white fish, reduced fat dairy, vegetables, lentils and fruit. Fat often carries a higher number of calories per gram than carbohydrates or proteins, so reducing your fat intake can reduce overall calorie intake.

You shouldn’t cut it out completely as it does play a useful role within our bodies, such as helping to keep our hair and skin healthy. Choose the healthier mono and polyunsaturated fats instead of saturated ones to protect your heart. Swap butter, lard, ghee, coconut and palm oils for small amounts of olive, rapeseed or sunflower oils or spreads. You can use a teaspoon or spray oil to measure out properly instead of pouring from the bottle.


Always go for the lean cuts of meat and make sure to trim off the excess fat before you cook it and remove skin if there is any. Avoid frying or roasting and try baking, boiling, grilling, poaching, microwaving or steaming, so you don’t add extra fat to it.

Replace foods such as crisps, biscuits, chips, samosas and donuts with fruit and vegetables. You can make your own salad dressings using ingredients such as balsamic vinegar, low fat yogurt and lemon juice with herbs. It is much healthier for you and tastes just as good.

Fats are high in calories, with 9 calories for every gram eaten, so we need to watch what kind of fats we have and make sure they’re the kind that will benefit us in some way.

Side Effects

Healthy fats promote positive cardiovascular health; so leaving out some of the good kinds can cause you problems later on in life, especially leaving out foods containing Omega-3.

You can have a vitamin deficiency, just like with the low-carb diet, as fats help your body to absorb and utilize fat-soluble vitamins such as A, D, E and K. If you can’t absorb these then you can develop some problems. Not only this, but eating too little fat can mess with your appetite control, as it increases food cravings.

Fat helps the brain to produce serotonin and dopamine, which are the chemicals that make us feel happy. They also help us to concentrate better, fight off low moods and foggy brain, which is something you definitely don’t want when you’re at work or the gym. A deficiency can lower moods significantly and increases stress and anxiety.


The Study

smiling female doctor with pills

There have been lots of studies in the past, the most recent being a six-day study. It may seem like it isn’t long enough to know anything but it was surprisingly. Low-carb diets have become more popular over the years. Most studies often show that low carb diets are just as good or better than other diets.

A study in the Cell Metabolism Journal was conducted by scientists on 19 adults with obesity on diets that avoided carbs and another that avoided fats. They ate 2700 calories a day on the study. Both led to loss of body fat but people lost more weight when they reduced their fat intake. Over two weeks their calorie intake was reduced by a third each day, by reducing either the amount of carbohydrates or the amount of fat.

The reduced carbohydrate group lost an average of 245g of bodyfat, whereas the group with reduced fat lost 463g.

The lead researcher Dr Kevin Hall, from the US National Institute of Diabetes and Digestive and Kidney Disease, said “With carb reduction you do lose body fat, but not as much as when you cut out the fat” and that there is no metabolic reason for people to opt for a low carb diet.

He went on to say that people need to stick to a diet that will work for them.

If it’s easier to stick to one diet than another, and to ideally do it permanently, then you should choose that diet. But if a low-fat diet is better for you, then you are not going to be at a metabolic disadvantage.


The meaning of this study was to show how your body treats carbohydrate calories differently from protein and fat calories. The low carb diet didn’t give dieters a fat-burning edges, which many people who love low-carb claim. However they did burn more fat for fuel, but had a smaller net fat loss because they took in more fat from food.

They predicted that the low-fat diet would continue to outperform the low-carb diet on fat loss over the long term, but the differences would be minimal.


Personal Preference

Professor Susan Jebb, from the university of Oxford, said:

The investigators rightly conclude that the best diet for weight loss id the diet that you can stick to. All diets ‘work’ if you stick to an eating plan that cuts calories, whether from fat or carbohydrate, but sticking to a diet is easier said than done, especially given the prolonged time it takes to lose weight.

Both diets have health benefits, as do a lot, so it really does come down to what you think is best suited to your health goals. Some people think that incorporating both is the way to go with high-quality carbohydrates and healthy fats, as it is rich in nutrients and can improve long-term health.

Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.

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