Ketogenic diets: Atkins and beyond

Ketogenic diets first came to the public’s attention with the Atkins diet and since then there have been lots of variations on ketogenic diets for weight loss.  The Dukan diet, along with many high protein diets, are basically all ketogenic diets that help you to lose weight.

HOW DO KETOGENIC DIETS WORK?

Our bodies prefer to use carbohydrates for energy.  When we cut carbohydrates out of our diet, then our body starts to use any fat that we have stored.  When you only use fat for energy, then your get high levels of ketones in your blood.  With carbohydrates out of your diet, you burn fat quite quickly so this approach is one of the faster ways to lose weight.  Most ketogenic diets start with the ketogenic stage and then gradually add carbohydrate foods back in.  This is because it is very difficult to follow such a restrictive diet and some of the side effects of a ketogenic diet are quite unpleasant.

WHAT ARE THE SIDE EFFECTS?

Following a ketogenic diet puts your body in a state called ‘ketosis’.  When your body is in ketosis, you generally have bad breath, constipation, headaches and other unpleasant side effects.  For many people, these are too uncomfortable and they give up this type of diet quite quickly.  Longer term, a high protein or ketogenic diet leads to an increase in some of the markers for bowel cancer.

DO KETOGENIC DIETS WORK?

Although you will lose weight faster at the start on a ketogenic diet, after 1 year your overall weight loss is no different whether you followed a ketgenic diet or any other weight loss plan. 

IS IT SAFE?

A ketogenic diet is quite safe in the short term but there are some real problems with staying on this type of diet for long.  It is very difficult to get enough fibre when you cut out all carbohydrate foods.  Although you can get fibre from vegetables, it is difficult to eat enough to get the full 25g of fibre you need everyday.  Normally we get fibre from wholegrains as well as beans and lentils. When these foods are cut out, fibre levels fall for most people.  Milk and yoghurt are also out on a ketogenic diet as they have the natural milk sugar lactose.  This means the ketogenic diet can be very low in calcium.  Although you can get calcium from green vegetables, you would need to eat 16 servings of broccoli a day to get all the calcium you need!!

ARE THERE ANY BENEFITS?

If you are overweight, then getting to a healthy weight can be beneficial for your health.  Most of us could also do with eating smaller servings of carbohydrate foods like bread, pasta and rice so these diets can help us to be more aware of how much we eat.  However, you can reduce your carbohydrates to 1/3 of your plate as one way of losing weight without having to cut them out altogether.  A ketogenic diet also forces you to eat more vegetables so lots of people do end up getting their 5-a-day.  However, you can also work on this yourself by making sure 1/3 of your plate is piled with vegetables at lunch and at dinner.

HOW CAN I LOSE WEIGHT HEALTHILY?

When it comes to weight loss, there is no ‘one-size-fits-all’.  Different things work for different people but most of us have a fair idea of some of the basic things that can help: smaller portions, smaller plates, limiting snacks to 1-2 per day and getting more active.  If you are really struggling, then you can find a dietitian to help you. You can also ask your GP to refer you to your local community dietitian.

Updated by members of the weight management interest group July 2016.Review date: July 2019.

© 2016 Irish Nutrition and Dietetics Institute, INDI. All rights reserved. May be reproduced in its entirety provided the source is acknowledged. This information is not meant to replace advice from your medical doctor or individual counselling with a dietitian.  It is intended for educational and informational purposes only.

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