Should I Eat a Low Carbohydrate Diet for Weight Loss?

Cutting carbs is a common weight loss strategy. 

From keto to more moderate low-carbohydrate approaches, low-carb diets are often praised for accelerating fat loss, controlling cravings, and improving metabolic health. However, misconceptions and confusion surround low-carbohydrate diets—do you need to cut carbs completely? Is it sustainable to eat a low-carb diet long-term? And should you eat a low-carbohydrate diet for weight loss?

In this blog, we’ll answer all these questions by diving into the science of exactly how a low-carbohydrate diet can help with weight loss. 

What is a low-carbohydrate diet?

A low-carb diet is any diet where a small proportion of your daily calorie intake comes from carbohydrates. Some examples of low-carb diets and eating patterns include: 

• The ketogenic diet (or keto diet)
• The Atkins diet
• The Paleo diet
• The South Beach diet
• And other Very Low Carb Diets (VLCDs)

The exact ratio of carbs required to make a diet count as low-carb is disputed, with research suggesting that diets containing anything from 5-40% carbohydrates count as “low-carb”.  

How does a low-carb diet help with weight loss?

The science behind low-carb weight loss

Many people turn to a low-carb diet with the hope that it will accelerate their weight loss. But how does this work?

A low-carb diet promotes weight loss by lowering insulin levels, encouraging fat-burning, and reducing appetite. Let’s take a closer look. 

Lower insulin, burn fat

Carbohydrates raise blood sugar levels, triggering the release of insulin. High insulin levels promote fat storage and block fat burning. 

By reducing carbs, a low-carb diet lowers insulin levels, allowing the body to access stored fat for energy. This is particularly beneficial for individuals with insulin resistance or metabolic syndrome.

A very low-carb diet (VLCD) has been shown to increase insulin sensitivity in older adults.

Fat as fuel and ketosis

Very low-carb diets (like keto) can push the body into ketosis. This is a metabolic state in which the body is using ketones from fat as its main energy source, rather than glucose from carbohydrates. 

The state of ketosis is not unique to low-carb diets, but serves as a mechanism to provide the body with an alternative fuel source during periods of caloric restriction. As such, ketosis can also be reached after an extended period of fasting, and is a goal of some intermittent fasting schedules.  

When it comes to weight loss, a keto diet isn’t essential. A non-ketogenic diet that maintains a caloric deficit will also lead to weight loss, while other low-carb diets can still promote fat burning by minimising insulin spikes.

Reduced hunger and cravings

Protein and fat—key components of a low-carb diet—are highly satiating.

• Protein boosts satiety hormones, such as GLP-1 and PYY, which help keep hunger in check.
• Fat slows digestion, stabilising energy levels and reducing cravings.

Studies show that people naturally eat fewer calories on a low-carb diet, even without strict calorie counting.

Low-carb vs low-calorie diet: Which is better?

If your goal is weight loss, you’ll need to maintain a calorie deficit—consuming fewer calories than you use. Whether you should eat a low-carbohydrate diet for weight loss vs a regular calorie deficit will depend on your goals and preferences. 

A low-carb diet focuses on reducing carbohydrate intake while prioritising protein and healthy fats. In contrast, a low-calorie diet reduces overall calorie consumption, regardless of macronutrient composition. While both can lead to weight loss, they work through different mechanisms.

A low-carb diet helps regulate insulin levels, reducing fat storage and encouraging the body to burn stored fat for energy. It can also naturally suppress appetite, leading to lower calorie intake without conscious restriction. This makes it particularly beneficial for those struggling with cravings, insulin resistance, or metabolic conditions like type 2 diabetes. However, to lose weight on a low-carb diet, you will still have to maintain a calorie deficit. 

While a low-carb diet isn’t required for weight loss, a calorie deficit is. 

Someone following a balanced low-calorie diet that includes carbs can still lose weight effectively. The advantage of a low-carb diet is that it may make maintaining a calorie deficit easier since many carbohydrate-rich foods are higher in calories. Similarly, a lower-carb diet may help to reduce hunger and stabilise energy levels.

The best diet for weight loss depends on your preferences and lifestyle. While a low-carb approach can be useful, some people may find that they adhere better to a diet that includes healthy carbs, such as whole grains and fruit, while still maintaining a calorie deficit.

Benefits of a low-carb diet (for weight loss and beyond)

Weight loss and fat reduction

Low-carb diets can promote weight loss and fat reduction by reducing insulin levels, increasing fat oxidation, and lowering appetite. Studies show that restricting carbohydrates leads to greater short-term weight loss than low-fat diets, partly due to water loss and increased satiety from a higher protein intake. 

A 2014 randomised trial published in the Annals of Internal Medicine found that a low-carb diet was more effective than a low-fat diet at promoting weight loss and improving cardiovascular risk factors. The same study reported enhanced fat loss and improved insulin resistance. 

While a low-carb diet doesn’t guarantee weight loss, the research suggests it can support it. 

Improved metabolic health

Low-carb diets can improve metabolic health by reducing insulin resistance, lowering triglyceride levels, and improving blood glucose control. Decreasing carbohydrate intake encourages the body to shift toward greater fat oxidation and reduced insulin secretion, resulting in improved glycemic regulation. 

A 2020 systematic review concluded that low-carb diets significantly reduced HbA1c levels and improved insulin sensitivity in people with type 2 diabetes, while a 2015 meta-analysis found that participants on low-carb diets experienced significantly lower predicted risk of atherosclerotic cardiovascular disease events than those on low-fat diets, highlighting a positive impact on cardiometabolic risk markers.

Better appetite control and reduced cravings

One key benefit of a low-carb diet is that it can improve appetite regulation and reduce cravings, especially for high-sugar and high-starch foods.

A 2015 randomised controlled trial found that individuals following a low-carbohydrate diet found significant differences in peptide YY (a satiety signal) between the low-carb and low-fat groups. Interestingly, there was no significant difference in ghrelin (another “hunger hormone”) between the two groups.

Similarly, research into keto diets has demonstrated that a low- or very low-carb diet can have a significant effect on appetite and satiety, helping to curb hunger throughout the day and minimise cravings.  These findings support the role of low-carb diets in naturally reducing caloric intake through appetite suppression.

Drawbacks of a low-carb diet

Potential low-carb diet side effects

Low-carb diets may cause short-term side effects such as fatigue, headaches, dizziness, nausea, constipation, irritability, and more. Combined, these symptoms are commonly referred to as “keto flu”. These symptoms occur as the body adapts to burning fat instead of carbohydrates, and are usually temporary. Staying well hydrated, replenishing electrolytes, getting good quality sleep, and avoiding intense workouts can help to make this more manageable.

Long-term considerations

The long-term safety and efficacy of a low-carb diet are debated. 

Maintaining a low-carb diet long term can lead to nutritional deficiencies, particularly in fibre, B vitamins, and certain minerals. Some individuals may also experience increased LDL cholesterol, while a diet that is consistently low in fibre can lead to digestive issues. Some research indicates that consuming a low-carbohydrate diet long term may be linked to the development of kidney stones and osteoporosis. 

Who can benefit most from a low-carb diet?

Some groups of people may benefit from a low or lower-carb diet, including: 

• Those who have struggled to lose weight on a higher-carb diet
• People with insulin resistance or type 2 diabetes
• Individuals with metabolic syndrome
• Those who naturally prefer a high-protein diet

However, a low-carb diet may not be a suitable choice for everyone. Those in the following categories may want to avoid a low-carb diet: 

• Individuals with certain medical conditions
• Athletes and highly active individuals
• People who struggle with dietary restrictions
• Those who are currently struggling with disordered eating or an eating disorder

If you’re unsure whether a low-carb diet is suitable for you, reach out to your GP or another registered medical professional to get the all clear before you start.  

Common questions about low-carb diets

Can you lose weight with a low-carb diet?

Yes, low-carb diets can lead to weight loss by reducing insulin levels, increasing fat burning, and promoting satiety, which helps reduce overall calorie intake. However, a low-carb diet is not the only way to lose weight—any diet with a calorie deficit will lead to weight loss. 

How many carbs per day should you eat for weight loss?

For weight loss, a low-carb diet typically involves consuming 50–150 grams of carbs per day. Very low-carb or ketogenic diets may restrict intake to under 50 grams daily. The ideal amount depends on your goals, activity level, and health status.

What are the best low-carb foods for weight loss?

The best low-carb foods for weight loss include non-starchy vegetables (such as spinach, broccoli, and cauliflower), lean proteins (chicken, eggs, fish), healthy fats (avocados, nuts, olive oil), and low-carb dairy (Greek yoghurt, cheese). These foods are nutrient-dense, promote satiety, and help maintain energy while supporting fat loss.

Can you build muscle on a low-carb diet?

Yes, you can build muscle on a low-carb diet, provided you consume adequate protein and engage in resistance training. While carbs support performance, muscle growth primarily depends on total calorie intake, protein quality, and training intensity, making muscle gains achievable even with reduced carbohydrate consumption. However, if your focus is on endurance or a more cardio-heavy sport, you are likely to need to include more carbohydrates in your diet. 

Is a low-carb diet safe long term?

While a well-formulated low-carb diet can be an effective weight-loss strategy in the short term, some research suggests that maintaining a low-carb diet long term can be detrimental. A 2019 longitudinal study found that a low-carb diet was positively associated with all-cause mortality across a large sample size. The study found that participants with the lowest dietary carbohydrate intake had the highest risk of cardiovascular disease, cancer mortality, and overall mortality. 

Need help deciding if a low-carb diet is right for you?

We hope this blog has served as a useful guide to the benefits and limitations of eating a low-carbohydrate diet for weight loss. 

If you’re looking for personalised nutrition support, our MVM Bespoke Nutrition Coaching could be for you. Reach out to the team at My Vital Metrics to find out more.