Low-Carb Diet: Complete Guide

What is a low-carb diet?

A low-carb diet (or carb diet in the sense of controlling carbs) is one where carbohydrate intake is reduced below the typical level–often to about 50–150 g per day, or 20–30% of calories–while protein and fat make up more of the diet. There is no single official definition: “low” can mean 50–100 g (moderate low-carb), under 50 g (very low-carb, close to keto), or in some plans under 20 g (no carb diet / carb free diet territory). A low carbohydrate diet is the same idea. Variations include: low carb diet for weight loss, low carb high fat diet (LCHF–often similar to keto), low fat low carb diet, low carb low sugar diet, the Zone diet (controlled carb/protein/fat ratio), the slow carb diet (slow-digesting carbs, no fast carbs), and the Dukan diet. A high carb diet is the opposite–more carbs, not low-carb.

There are no mandatory phases for a simple low carb diet plan; you set your carb target and follow it. Some programmes (e.g. Dukan) have phases. A low carb diet meal plan or no carb diet plan (or no carbs diet plan for 2 weeks style) can give you structure; low carb diet recipes help you build meals. Use our TDEE calculator to tailor calories if needed.

Core principles

• Reduce total carbohydrates (bread, pasta, rice, sugar, starchy vegetables, many fruits).
• Eat adequate protein (meat, fish, eggs, dairy, legumes in moderation).
• Use fat for energy and fullness (especially in a low carb high fat diet / LCHF diet).
• Focus on low carb diet foods: non-starchy vegetables, nuts, seeds, healthy oils.

How the low-carb diet works

When you eat fewer carbs, your body has less glucose from carbohydrates and may burn more fat for energy. In a low carb diet for weight loss, you often eat in a calorie deficit because you cut a major calorie source and may feel less hungry (protein and fat can increase satiety). Weight loss still depends on burning more calories than you consume; a low carb diet is one way to get there. Very low-carb plans (e.g. no carb diet) can put you in ketosis–see our keto diet guide for that approach.

There are no universal phases. You can start with a low carb diet plan or low carb diet meal plan that fits your carb target (e.g. 100 g or 50 g per day). Some people try a low carb diet weight loss in 2 weeks style challenge; for long-term results, a sustainable low carbohydrate diet that you can maintain usually works better than a short, very strict burst.

What to eat and what to limit on a low-carb diet

Low carb diet foods are those that are low in carbohydrates. The table below summarises what to emphasise and what to limit. Exact limits depend on your chosen carb level (e.g. 50 g vs 100 g per day).

When planning low carb diet meal plan meals, base each meal on a protein source and non-starchy vegetables, and add fat as needed. Low carb diet recipes often use cauliflower rice, zucchini noodles, or other low-carb swaps for grains. A low carb high fat diet or LCHF diet emphasises fat (e.g. avocado, olive oil, butter); a low fat low carb diet keeps fat moderate and leans on protein and vegetables. The slow carb diet allows certain legumes and avoids “fast” carbs; the Zone diet uses a fixed ratio of carbs, protein, and fat.

Potential benefits of a low-carb diet

Benefits are often described as “may” or “in studies”–individual results vary.

• Weight loss: A low carb diet for weight loss can help when it leads to a calorie deficit. Short-term trials often show weight loss on low-carb diets; long-term comparison with other diets is mixed–adherence matters.
• Blood sugar: Reducing carbs can lower blood glucose and insulin in some people. If you have diabetes or prediabetes, any change should be supervised by your doctor (medication may need adjusting).
• Satiety: Protein and fat can increase fullness, which may make it easier to eat less without feeling hungry.

Quality of evidence: short-term weight loss is well documented; long-term and comparative evidence varies. Talk to your doctor about whether a low-carb diet is appropriate for you.

Risks and who should be cautious

Low-carb diets are generally safe for many people in the short to medium term. A few points:

• Fibre and nutrients: Very low-carb or no carb diet plans can be low in fibre and some vitamins if they cut out whole grains, legumes, and fruits. Include plenty of non-starchy vegetables and consider variety.
• Diabetes: If you take insulin or other diabetes medication, reducing carbs can affect blood sugar and medication needs. Work with your doctor before changing your diet.
• Kidney disease: High protein intake (common on low-carb) may need to be adjusted if you have kidney problems. Check with your doctor.

Before starting a low carb diet plan or no carb diet plan, especially if you have a health condition, consult your doctor or a registered dietitian.

Sample low-carb diet day (meal ideas)

This is one example of meals that fit a low carb diet–not a prescriptive plan. Adjust portions and carb level to your target.

• Breakfast: Scrambled eggs with spinach and cheese; or Greek yogurt (plain) with berries and nuts; or an omelette with vegetables and avocado.
• Lunch: Salad with grilled chicken or tuna, olive oil, and avocado; or lettuce wraps with minced meat and vegetables; or salmon with asparagus and butter.
• Dinner: Grilled meat or fish with cauliflower mash and broccoli; or stir-fried vegetables with chicken and a small portion of rice (if you allow some carbs); or a low-carb casserole with meat and vegetables.
• Snacks: Cheese, olives, nuts, raw vegetables with dip, or a small portion of berries.

For more structure, use a low carb diet meal plan or low carb diet plan from a reputable source or dietitian. Low carb diet recipes can help you vary meals. If you want very low carbs and ketosis, see our keto diet guide; if you want more protein focus, see our high-protein diet guide.

Frequently asked questions about the low-carb diet

Summary

A low-carb diet (or low carbohydrate diet) restricts carbs–often to 50–150 g per day–and emphasises low carb diet foods: meat, fish, eggs, non-starchy vegetables, nuts, and healthy fats. It is commonly used for low carb diet for weight loss and can support blood sugar control when done with medical guidance. It is less strict than the keto diet; variations include low carb high fat diet (LCHF), low fat low carb diet, Zone diet, and slow carb diet. Before starting a low carb diet plan or low carb diet meal plan, especially if you have diabetes or kidney disease, talk to your doctor. Use our calorie calculator and TDEE calculator for weight goals. For related approaches, see our keto diet, high-protein diet, or weight loss diet guides.

Use our calculators with this diet

Set your calorie target and plan meals with our free tools.

Sources and further reading

This article is based on current scientific and clinical sources. For more detail, see:

• NIH and national dietary guidelines on carbohydrate intake and weight management
• Systematic reviews on low-carbohydrate diets vs other diets for weight loss and metabolic outcomes
• American Diabetes Association: nutrition therapy for adults with diabetes (carbohydrate and diet patterns)

Last updated: 20 February 2026. Content is for educational purposes only and does not replace medical advice.