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The Pros and Cons of the 40/30/30 Zone Diet

Most modern-day diets tend to be restrictive, eliminating certain foods, ingredients and even entire macronutrient groups. The 30/30/40 Diet is quite different in that it incorporates a moderate amount of protein, carbohydrate, and fat into an overall plan.

Here’s what a sample day of eating would look like following a 40/30/30 macronutrient split:


  • 3 scrambled eggs
  • 2 slices of whole grain toast
  • 1/2 an avocado


  • 1 apple
  • 1 oz. almonds


  • Grilled chicken breast (4 oz.)
  • Quinoa (1 cup)
  • Steamed broccoli


  • 1 scoop of protein powder
  • Blueberries (1/2 cup)


  • Salmon (4 oz.)
  • Brown rice (1 cup)
  • Roasted Brussels sprouts (1 cup)

It's important to note that this diet is just a template. Your individual macronutrient needs will vary based on individual factors such as gender, age, activity level, and goals.

Should you jump aboard ship, or is this just another fad diet that you should just ditch altogether? 

What is the 40/30/30 Zone Diet?

Also known as the Zone Diet, the 30/30/40 Diet adopts the "moderation is key" principle, focusing on moderate amounts of protein, carbohydrates, and fat within the plan. This approach doesn’t restrict a certain food group, and it places a strong emphasis on quality food sources. The general plan suggests basing your daily diet around 40% carbohydrates, 30% protein and 30% fat.

Pros of the 40/30/30 Diet

No exclusion zone

Unlike many other diet plans, the 30/30/40 Diet seeks to integrate food groups rather than eliminate them. A diet that promotes inclusivity rather than exclusivity is more likely to lead you to long-term success. Low-carb diets leave you lacking energy, while low-fat diets can wreak havoc on your hormones. Carbohydrates such as rice and sweet potato contain high amounts of fiber and a gradually-digesting energy source. Fats are also integral for absorbing vitamins and minerals into the bloodstream. Integrating a moderate amount of all macronutrients is also pretty achievable, so you’d be far more likely to follow this plan with success.

Evidence does exist

The University of Illinois at Urbana-Champaign conducted a study in which two diets were analyzed: one which adopted a 30/30/40 approach, and another with higher carbohydrate and much lower protein. They discovered that the 30/30/40 diet promoted greater weight loss and greater retention of lean muscle mass. Protein consists of amino acids proven to build and repair muscle tissue. The higher protein quantity seen in the 30/30/40 diet is likely to be responsible for this retention of muscle mass and emphasizes the importance of macronutrient balance.

Proper preparation

Many people are put off the 30/30/40 Diet by the measures needed to ensure macronutrient targets are being met. This does sound like a daunting task, but not if you put in adequate prep first. If you set aside an hour or two each night, you can carefully prepare your meals using all the foods you enjoy – in accordance with the amount of protein, carbohydrates, and fat you need.

Cons of the 30/30/40 Diet

Miscalculated calories

The true driving force behind weight loss is calorie expenditure. That is, if you’re burning more calories than you take in through food and drink, then you’ll lose weight. Macronutrients are hugely important, but there is always the chance that you could lose sight of your calorie intake by focusing too heavily on your ratio of protein, carbohydrates, and fat.

Lost sight of success

Chief creator of the 30/30/40 Diet, Dr. Barry Sears stated that men following the plan were to consume 1500 calories per day. You already know calories are key to losing weight, and the average human burns 2000 calories each day purely by existing. Consuming a mere 1500 calories per day will result in weight loss irrespective of whether you eat a wholesome diet or a greasy plate of pizza. You could also argue that this figure is further limited once you take training into account. Energy requirements become even higher with a grueling training session on the agenda.

Individual differences

The problem with a ‘one-size-fits-all’ diet like 30/30/40 is that it doesn’t take individual needs and differences into account. For instance, you could work in an office, sat at a desk all day leading a sedentary lifestyle. Here, your carbohydrate quota would need to be lower than that of someone working in a more physical industry such as construction. When you introduce training or sport into the equation, food becomes further complicated. 

The 30/30/40 Diet: The Overall Opinion

Success on the 30/30/40 Diet owes more to a calorie deficit than any specific macro split. Adopting a set ratio of protein, carbohydrate and fat is a bit restrictive if you haven’t first considered your own lifestyle. If weight loss is your goal, you should first work out your activity level, and compared with figures such as the Basal Metabolic Rate, you can obtain a targeted calorie count. Sticking to this and extracting your macronutrient ratios from this is a far more efficient way of smashing your goals.

A diet like the 40-30-30 approach has several benefits because it’s based around moderation

  • Sustainability: Since a balanced dietary approach doesn’t eliminate entire food groups or require extreme drops in caloric intake, it’s generally easier for people to maintain long term. This is important because long-term success with any type of diet depends on compliance with the plan.
  • Balanced nutrient intake: A moderate diet that has a balanced intake of all your macronutrients (protein, carbohydrates, and fat) sets you up for better success when it comes to covering your bases for your micronutrient intake (vitamins and minerals). By consuming a wide variety of nutrient food sources, you increase the likelihood that you’re consuming enough of the various micronutrients your body needs.
  • Flexibility: A moderate diet can be easier to incorporate into your lifestyle because you have less strict rules to adhere to. This can help reduce feelings of deprivation, anxiety, and stress associated with strict dieting. This approach can also help shape your overall relationship with food.

Adding a protein powder supplement to your routine can also help with hitting the precise macronutrients you need for success with the 30/30/40 diet.

Whey Sport: Cellucor Whey Sport contains 30g of high-quality whey protein to help turn recovery time into muscle-growing time, and is ideally formulated for however you move by being gluten and soy-free and low in carbs, fats, and sugars.

COR Performance Whey: Every two scoops of COR-Performance Whey Isolate Protein Powder is packed with 24g of fast-acting whey protein and digestive enzymes so that you can satisfy your protein needs anytime of the day.

Date August 06, 2018
Category Nutrition