What Foods Can You Eat on the Cambridge Diet?

The Cambridge Diet, now known as The 1:1 Diet, has helped hundreds of thousands of people lose weight over the last 35 years. This very low-calorie diet (VLCD) involves consuming a structured combination of proprietary meal replacements and, in later stages, regular food to achieve significant weight loss. What you can eat is determined by which of the plan's six steps you are following, with a gradual increase in conventional foods as you progress.

Quick Summary

The Cambridge Diet, rebranded as The 1:1 Diet, is a phased weight loss plan where dietary options depend on which of six steps you are following. It starts with proprietary meal replacements and later introduces conventional foods under the guidance of a consultant.

Key Points

• Phased Plan: The Cambridge Diet (now The 1:1 Diet) is structured in six steps, moving from meal replacements to conventional food gradually.

• Sole Source: The initial phase involves consuming only proprietary Cambridge Diet meal replacements like shakes, soups, and bars, with a daily calorie intake of 400-600 calories.

• Introducing Real Food: As you move to later steps, conventional foods like protein-rich items, skimmed milk, and vegetables are reintroduced.

• Nutritionally Balanced: All Cambridge Diet meal replacement products are formulated to provide essential vitamins and minerals despite the low calorie count.

• Consultant-Led: The diet is conducted under the supervision of a consultant who helps guide you through the different stages and product choices.

• Emphasis on Water: Sufficient hydration is crucial, with dieters advised to drink at least 2.5 litres of water per day, especially in the early phases.

Understanding the Cambridge Diet: The 1:1 Diet Plan

The Cambridge Diet, developed by Dr. Alan Howard and now known as The 1:1 Diet by Cambridge Weight Plan, is a structured weight loss program that operates in six distinct steps. Each step progressively increases the daily calorie intake, moving from a sole reliance on specially formulated meal replacements to a more balanced diet incorporating regular, healthy foods. The fundamental principle involves creating a significant calorie deficit, which can lead to a metabolic state called ketosis, where the body burns stored fat for energy. All products, including shakes, soups, and bars, are designed to be nutritionally complete to avoid deficiencies despite the low calorie count. A personal consultant guides dieters through the process, helping them transition between steps and make suitable food choices.

Foods Allowed and Restricted by Step

What you can and cannot eat on the Cambridge Diet is strictly controlled and depends entirely on the step you have been assigned by your consultant. The plan ensures nutritional requirements are met through its products, with normal foods being carefully and gradually reintroduced.

Step 1: Sole Source (415–600 calories)

• Allowed: The only food permitted during this phase is 3-4 Cambridge Diet meal replacements daily. This may include shakes, soups, or porridge from the product line. Dieters must also consume at least 2.5 litres of water.
• Forbidden: All conventional foods, including fruits, vegetables, meat, and dairy, are restricted.

Step 2: (810 calories)

• Allowed: This step introduces some conventional food alongside two Cambridge Diet meal replacements. Permitted additions include protein-rich foods, non-starchy vegetables, and 1/5 pint of skimmed milk.
• Forbidden: The majority of carbohydrates, fats, and high-sugar items are still prohibited. Alcohol is not allowed.

Step 3: (1,000 calories)

• Allowed: In this two-week phase, the diet consists of two Cambridge Diet meal replacements plus skimmed milk, a low-calorie breakfast, and a salad for lunch and dinner.
• Forbidden: High-calorie foods, snacks, and most fats remain restricted.

Steps 4 and 5: (1,300 and 1,500 calories)

• Allowed: These steps increase flexibility further, featuring two Cambridge meal replacements alongside breakfast, lunch, and dinner. The calorie intake increases to 1,300 and 1,500 respectively.
• Forbidden: The focus shifts to healthy eating, but processed foods, sugary snacks, and alcohol are still discouraged.

Step 6: Maintenance (1,500+ calories)

• Allowed: The final step is maintenance, where you eat a regular healthy diet supplemented with one or two Cambridge Diet products as needed. This helps manage weight indefinitely.
• Forbidden: High-calorie, unhealthy foods should be avoided, and healthy eating principles learned throughout the plan should be applied.

A Comparison of Food on the Cambridge Diet vs. a Traditional Diet

Feature	Cambridge Diet (Initial Phases)	Traditional Balanced Diet (Maintenance)
Food Sources	Specially formulated meal replacements (shakes, soups, bars, etc.).	Whole, unprocessed foods (lean proteins, whole grains, fruits, vegetables).
Calorie Control	Very low-calorie intake, strictly controlled by specific products.	Calorie-controlled meals, but with more flexibility and variety.
Carbohydrates	Very low to non-existent; carbs are eliminated to induce ketosis.	Includes complex carbohydrates from whole grains, fruits, and vegetables.
Nutritional Content	Nutritionally complete, with added vitamins and minerals in products.	Nutrients are derived from a wide variety of food groups.
Meal Preparation	Minimal to no preparation, as products are ready-made.	Requires regular meal planning and cooking.
Long-Term Sustainability	The initial restrictive phases can be challenging for long-term adherence.	Teaches sustainable eating habits for long-term weight management.

Conclusion

The Cambridge Diet offers a highly structured, phased approach to rapid weight loss by using specially formulated meal replacements in the initial stages. As you progress through the plan's six steps, conventional, healthy foods are gradually reintroduced, teaching dieters how to transition toward a sustainable, balanced diet for long-term maintenance. The success of the diet is heavily reliant on sticking to the specific products and guidelines, particularly during the very low-calorie initial phases. While effective for rapid weight loss, the highly restrictive nature of the early stages means it is not a suitable long-term solution for all individuals and can be costly. Anyone considering this diet should consult a healthcare professional to ensure it aligns with their health needs and goals.

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For more information on Very Low Calorie Diets, you can explore resources from the National Institutes of Health(https://pmc.ncbi.nlm.nih.gov/articles/PMC6282840/).

Frequently Asked Questions

What is the Cambridge Diet?

The Cambridge Diet, now known as The 1:1 Diet, is a very low-calorie weight loss program structured in six phases. It primarily uses nutritionally complete meal replacement products and, in later stages, incorporates conventional food.

What can you eat during the initial stages of the Cambridge Diet?

In the initial 'Sole Source' stage, you can only eat 3-4 Cambridge Diet meal replacements per day, such as shakes, soups, or bars. The caloric intake is between 415-600 calories daily.

When can you start eating regular food on the Cambridge Diet?

Regular food is gradually introduced starting with Step 2, where you replace some meal replacements with protein-rich foods, vegetables, and skimmed milk. The variety and quantity increase with each subsequent step.

Can I have fruit on the Cambridge Diet?

Fruit is typically restricted during the most intensive phases of the diet. It may be reintroduced in later, less restrictive steps, but should be managed according to your consultant's guidance.

Is alcohol permitted on the Cambridge Diet?

No, alcohol is not permitted on the Cambridge Diet, especially during the initial phases, as it can interfere with ketosis and is high in empty calories.

Do I need a consultant for the Cambridge Diet?

Yes, a key feature of The 1:1 Diet is the one-on-one support from a consultant who helps tailor your plan, provides products, and monitors your progress.

What happens in the maintenance phase of the Cambridge Diet?

In the maintenance phase (Step 6), you transition to a regular, healthy diet, using a Cambridge Diet product as needed to help sustain your weight loss. The daily calorie target is around 1,200 calories or more, depending on your needs.

What types of Cambridge Diet products are available?

The product range includes a variety of options such as shakes (chocolate, vanilla, etc.), soups (tomato, leek & potato), bars (chocolate chewy, lemon yogurt), porridge, and savory meals like macaroni cheese and chili con carne.