How Much Carbohydrate Should I Be Eating?

How Much Carbohydrate Should I Be Eating?
Patients need to understand the types of foods which will effect their blood glucose levels, which I have previously blogged about here. After this, the next logical question, and a question I am often asked, is how much carbohydrate shall I be eating. This is always a tricky question to answer because the answer depends on many factors. Examples like the patients lifestyle, weight, type of diabetes, activity levels, medications, amongst many other variables effect the answer. However, I thought I would try to see today if I can offer some insight into getting a better idea about what is correct for you. I have broken the categories down into the type of medications you may be taking because these may effect our considerations in terms of your diet.

But first, General Healthy Eating

Before we get into this, it is worth mentioning the general healthy eating guidance recommend to everyone in the UK. This is assuming there isn’t a special diet you are following for medical purposes. The healthy eating advice isn’t too far removed from the advice for type 2 diabetes and so is worth a read. You should aim for the following:
  • 5 fruit or vegetables per day MINIMUM. The ‘minimum’ tends to be the missing part of this message. This results in some of my patients achieving 3 portions and thinking they are close enough. I would suggest at least 3 of these portions come from vegetables and 2 from fruit. In fact, generally when it comes to vegetables the evidence appears to show it is a case of the more the better. Hence, the confusion frequently reported in the media about ideal levels. For reference a portion of vegetables is 4 tbsp and a portion of fruit is either 2 small fruits, 1 medium fruit or half a large fruit.
  • At least 2 litres of fluid per day. Unfortunately for the wise cracks out there, this doesn’t count alcohol! This counts from any fluid you may have including milk, soup, tea, coffee, water, juice etc. The recommendations are no more than 6 teas per day or 4 coffees, no more than 125ml of juice and keeping alcohol to a minimum. Therefore, you do not have to just count water.
  • Keep processed sugar and processed foods to a minimum.
  • Aim for tennis ball sized portions of starchy carbohydrates at meal times adding bulk to the meal using vegetables and lean protein sources.
  • Keeping added salt to below 6g (a teaspoon) per day.
  • Aim to have fish twice per week aiming for at least one oily portion. Alternatively, have a teaspoon of olive oil or rapeseed oil, a handful of nuts or seeds or avocado twice per week to ensure you meet your healthy fats requirement.
  • Aim to achieve at least 150 minutes of moderate intensity activity per week. Moderate intensity is defined as a brisk walk or any activity where you feel slightly hot and your breathing rate has noticeably increased.

How much carbohydrate

1. Diet Controlled

If you are diet controlled, this is a good opportunity to improve your long term outcomes. You are essentially a blank canvas whereby you can make dramatic lifestyle changes to reduce your chances of needing medication or significantly pushing back your need for medication. Generally speaking, I am referring to those who are still young enough to see the long term complications manifest. For example, a 40 year old has more chances of long term complications compared to a 78 year old. In the diet controlled group, following the above guidelines would be a great start. However, we can get even more specific. Dedicating half a plate to vegetables will dramatically reduce your calorie intake. It will also help to cut down on the foods which will effect your diabetes i.e. carbohydrates. The amount of carbohydrate you require will depend on your activity levels. Typically speaking, those who achieve less than 5000 steps per day will need very little carbohydrates to keep them going. You may find you only need somewhere between 100-120g per day. This is not a rule but a general observation from experience with patients. In fact, at very low activity levels, you may find you do not need to eat carbohydrate at every meal. Compared to someone who is on a intermediate or mixed insulin regimen who will likely require carbohydrates at every meal, diet controlled patients may find reducing their carbohydrates translates into better glucose control and weight loss. As you begin to get more active, you may find you can eat more carbohydrates but sticking with the above tennis ball portion size is a good start.

Oral Tablet Controlled

As more tablets are added to your diabetes prescription, the further the disease is progressing. This is a good indicator it could be time to look at your lifestyle. Your doctor will be aware of the lifestyle benefits and may even recommend some changes. Remember though, their job is to keep your diabetes under control and they only have a very short time to do it. So if they see a big rise in your blood glucose levels between reviews, it is likely they will prescribe further medication to help bring the blood glucose levels rather than discuss lifestyle approaches. The problem with this approach is it does not address the underlying issue, which in type 2 diabetes, is generally weight issues, too large portions at meal times and/or too much unhealthy food. This cohort of patients will likely benefit from implementing similar changes to diet controlled only. Therefore, focus should be paid to reducing the carbohydrate portions at meals and following the general healthy eating principles outlined above.

Once Daily Long Acting Insulin

Once daily insulin has quite a flat profile with regards to how it works. In other words, your diabetes has reached the point where your pancreas is no longer producing enough insulin to keep your diabetes under control but it still has enough function that a ‘mild insulin; (for lack of a better expression) controls it. The dose of insulin will be a good indicator of how much function is lost from the pancreas and how insulin resistant your body’s cells have become. For example, someone on 8 units has better function than someone on 44 units. However, because once daily long acting insulins such Levemir, Lantus, Abasaglar and/or Tresiba are quite flat in profile, it is quite easy to ‘out eat’ their action. This is highlighted in my rather awful diagram below. Basal Insulin With such insulins, it is recommended to avoid eating large portions of carbohydrates at meal times. I would also recommend not stacking various carbohydrate sources on top of each other e.g. rice, followed by fruit and a dessert. This is will likely see a spike in your blood glucose levels as highlighted in the above diagram. Those on a long acting insulin may find eating little and often helps them with their blood glucose control but ultimately the healthy eating advice above will also add benefits.

Intermediate or Mixed Insulin

These insulins have a more pronounced profile meaning they are a step up from the long acting insulins outlined above. Examples, include Insulatard, Novomix 30, Humulin I, Humulin M3 etc. You may find such insulins are recommended when a once daily long acting insulin doesn’t keep your blood glucose levels under control. These can be administered once, twice or three times per day depending on your individual circumstances. They last approximately 12 hours before their action begins to wear off hence why sometimes they are administered twice daily. They are usually given with food to help reduce the blood glucose spike caused by eating. Therefore, these insulins are prescribed on the assumption you will continue to eat carbohydrates. The profiles are highlighted in another of my awful diagrams below. Mixed insulin The problem with these insulins is a proportion is only for the carbohydrates in your food. Therefore, any dietary changes may cause low glucose levels.  Therefore, eating a regular carbohydrate intake is usually necessary because the insulins profile. Therefore, if you take a mixed insulin, it is recommended you include some form of carbohydrate at each meal to prevent your blood glucose levels dropping too low. As a result, you may find you eat slightly more carbohydrate than your diet controlled counterpart. That doesn’t mean you still cannot make lifestyle changes conducive to better diabetes control. Once again, utilising the tennis ball carbohydrate portion size at each meal should be enough to prevent rapid drops in blood glucose levels but please be aware that if you are making big changes to your diet you may need to also consider adjusting your insulin dose and speak with your team.

Basal Bolus Regimen

Those following a basal bolus regimen (likely type 1 or type 3 diabetes but also found in some type 2s) are no different from any other dietary recommendations for health and we still advise following a healthy diet. However, those following a basal bolus regimen should ideally be following some form of carbohydrate counting system to help them match their rapid acting insulin doses to their carbohydrate intake. I have recently blogged about this which you can read here.  Therefore, I won’t dwell on this as the basics are covered in the above article.


Hopefully this article has cleared up some questions for you but you can see from even just looking at medications alone it is difficult to provide generic advice. Generally speaking, the healthy eating advice explained at the beginning of this article stands true for most types of management and most types of diabetes. There is no ideal carbohydrate intake as this will vary from person to person. A great way of analysing whether your dietary intake is working for you and your diabetes is to see how your control is at your next diabetes check up. If your nurse tells you your control could be improved, then it’s time to work backwards and see where changes can be made. If your nurse says you’re doing great but you are on several tablets a day and insulin, it may be the medications doing the job for you. If you are on minimal medical intervention, have good diabetes control but still recognise you are carrying extra weight, now is the time for a a weight loss plan and/or lifestyle change. This opportunity may not come again. Ultimately, everyone suffering from diabetes will benefit from making healthier changes but the longer you leave a lifestyle change, the harder it will be to get your diabetes under control long term.

Need more help

If you need more support we offer a range of 1:1 consultancy services and online programmes focused on helping you improve your glucose control and health for the long term. These include our type 2 diabetes recovery programme, type 1 glucose stability programme and winning weight loss programme. Go to the pages using the links above or in the headers or get in touch if you have questions.

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