gi diet plan

The GI or Glycemic Index

The Glycemic Index was developed by Dr David Jenkins. It's essential a value that is assigned to foods based on how quickly, and how high those foods cause increases in your blood glucose levels.

Whether your spell it Glycemic or Glycaemic, the values of individual foods can be used to help you plan a diet that works for you. In essence, the Glycemic Index ranks foods out of 100 as a way of measuring how quickly they would break down to form energy.

The Basics

The advantages of understanding the GI (or Glycemic Index) of a food is that you can figure out what foods take longer to be broken down and therefore give you longer until you feel hungry again.

The glycemic index ranks food on a scale from 0 to 100 with the low end of the scale (0-55) having foods that have little effect on blood sugar levels. The high end of the scale has foods with a big effect on blood sugar levels (70+).

The point is that you won't end up suffering from that gnawing hunger pang or feeling of starvation if you choose the right GI foods.

GI plans are all based on the Glycaemic Index Chart, a rating of the "speed" at which the body processes different foods and sends the sugar to your bloodstream. You will find loads of books and charts that list different foods - the index range is as follows:

  • Low GI = 55 or less
  • Medium GI = 56 - 69
  • High GI = 70 or more

You want to be aiming for the Low GI foods - they take the longest to breakdown.

Ideally you should choose as many foods as possible from the low and medium categories, only occasionally eating from the high group - for example, right after a tough workout, when your body's energy supplies are depleted.

Why Is This Useful?

Eating this way is an effective way to control your weight, particularly for those people who usually have a very sugary diet - it forces you to look at how much over-refined and over-sugared food is in your diet.

Following this diet plan means you are far less likely to damage your health as there's no drastic deprivation involved or eliminating essential food groups. Instead, a scientific understanding of how the body breaks down food to produce glucose for energy is used to give you practical advice on how to lose weight with the minimum of discomfort. Its realistic, simple to follow, and not for masochists.

So How Can the GI Plan Help?

The Glycemic Index 'diet' will help you lose weight by helping you decide on what foods to eat based on how different foods are absorbed into the bloodstream at different rates. By choosing foods that are relatively low in calories but which the body uses slowly, you will feel full for longer and so resist the urge to snack or eat more than you need.

The GI Plan also uses a simple colour coding system to help guide you as to which foods to eat. Green is for 'Go' and these represent foods where you can happily consume as much as you like.

Orange is for 'slow down' so these foods are okay to be eaten on a moderate basis. Red is for 'stop' and these foods are non-starters if you're hoping to shed those pounds. So theres no complicated calorie counting and weighing up of options, it couldn't be more straightforward.

It is not an instant solution, however, it is important to still important to consider other factors such as portion size, and the total quantity of food you eat.

You also have to be careful not to eat too much fatty food - fatty foods score low on the index, but should not be eaten in large quantities.

What Foods are GI?

Eating GI foods has nothing to do with American soldiers, and everything to do with how the food you eat affects your blood sugar levels.

The Glycemic index is a ranking of foods based on their immediate effect on blood glucose (blood sugar) levels. Carbohydrate foods that breakdown quickly during digestion have the highest Glycemic indexes. Their blood sugar response is fast and high. Carbohydrates that breakdown slowly, releasing glucose gradually into the blood stream, have low Glycemic indexes.

Eating low GI foods has many benefits, including:

  • Helping to control diabetes
  • Helping people lose weight
  • Lowering blood lipids
  • Improving the body's sensitivity to insulin

At the other end of the spectrum, high GI foods are great for re-fuelling your carbohydrate stores after exercise.

The Glycemic index is determined in large part by the soluble fibre content, fat content, and type of sugar that make up the food. Higher levels of fat and fibre slow the absorption process.

Foods are therefore rated according to how quickly the carbohydrates are metabolised. As suggested above, those with a high rating release their energy quickly, and are best just after a workout, while foods low in the GI index are best later in the day, and before a workout.

The best policy is to eat a low GI snack two hours before your workout. If you can't do that, the alternative is to eat something that is high on the GI index just before you workout to be sure you don't run out of fuel half way through.

For those looking to lose weight, it is best to focus on foods lower on the GI index. Foods with a high GI index rush sugar into your bloodstream and initiate an excessive insulin response - this prompts the body to store more fat. In addition, because you feel less satisfied, you get hungry sooner and want to eat again - this cycle is endlessly repeated by those people who eat lots of high GI foods.

To get you started, the following lists show the GI scores of some popular foods:

Low GI:

  • Apples
  • Beans (kidney)
  • Broccoli
  • Cantaloupe
  • Cauliflower
  • Cherries
  • Grapefruit
  • Grapes
  • Peaches
  • Peanuts
  • Plums
  • String Beans

Medium GI:

  • Apricots
  • Beans (garbanzo, lima, navy)
  • Bread (pumpernickel, rye)
  • Candy Bars
  • Ice Cream
  • Milk
  • Oatmeal
  • Oranges
  • Orange Juice
  • Pasta
  • Peas
  • Tomato Soup
  • Yoghurt

High GI:

  • All-Bran Cereals
  • Bananas
  • Bread (wheat, white)
  • Carrots
  • Corn
  • Corn Chips
  • Low-Fat Ice Cream
  • Instant Mashed Potatoes
  • Potato Chips
  • Puffed Rice Cakes
  • Raisins
  • Rice


This is a popular diet plan that actually helps you to follow basic healthy eating guidelines!

You get to eat lots of fruit and veg and you are advised to reduce refined and sugary carbohydrates as they are in the high GI category (or red zone). 

We think that if this sounds like the plan for you, then don't forget some basic diet principles.

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