Diet Review: The Alkaline Diet

This is the start of a review of a number of mainstream and celebrity based diets. The fitness and nutrition industry is awash with various plans backed with flaky science. In this series I am considering the positives and negatives of each of these plans.

Not only do diets now promise weight loss. They also promise to “detox” us, reset our body’s metabolism and make it abundantly clear that we do not have a clue how or what to eat. One such diet suggests that not only will this diet cure cancer but it will reset the bodies pH and allow the immune system to regain control of the body before it consumes you in one big anti-human explosion which clearly you didn’t stand a chance of staying alive or even functioning if you didn’t consume predominantly alkaline food.

The premise behind this type of plan is that pH is a measure of the balance of acidity and alkalinity (think back to school science). A pH of 0 is extremely acidic, 14 is extreme alkaline. Therefore a pH of 7 is neutral. Now our body has a number of different areas that are separate to each other which need differing levels of acidity and alkalinity. For instance, the stomach has a pH ranging from 1.3 to 3.5, in turn blood has to remain slightly alkaline between a pH of 7.2 (during exertion) and 7.45.

The idea behind the diet is that you can influence the pH of your body by undertaking the consumption of alkaline foods. This in turn leads to in the diets description enhanced function of the body- meaning a loss of weight and a detox from an acidic state in turn putting your body “back in to balance.”

The issue is that the body is pretty good at doing this. The body’s pH has to stay a different ranges in it’s different places for a number of reasons. Mainly that certain reactions need to take place. Stomach acid for one needs to be acidic to break down consumed proteins. Blood needs to be slightly alkaline as to filter waste products from the body, the increase in carbon dioxide during exercise is a good example of how increase in pH results in an increase in the amount of oxygen released. Large fluctuations in blood pH are dangerous so therefore the body keeps a tight reign on them, too far either way and you are probably looking at multiple organ failure.

The diet in itself is mainly vegetarian (a swear word in my presence). It is made up of certain types of vegetables, soy products, certain fruits and limited grains. Acid foods are to be avoided including meats, lentils (they have been wanting to get on a naughty list for some time), dairy foods, fats, oils and anything else fun including alcohol and caffeine.

So what are you left with? Lots of fruit and vegetables with zero processed food. Simply, a low protein, vegetable based carbohydrate diet with limited fat.

What effect will this diet have on the pH of the body- well it will have limited effect on blood pH but you may see a change in urine pH. It has been shown that diet can effect urine pH so therefore the line has been drawn between urine pH and the acidity of the body. The key with this is two organs are mainly responsible for blood pH- the lungs and the kidneys. The lungs as stated earlier regulate carbon dioxide (acid) the kidneys reabsorb bicarbonate from the urine and also excrete hydrogen ions- hence the increase in pH is related to hydrogen ions. This would indicate that hydrogen ions are negative in relation to health rather than what they are- products related to the process of protein and amino acid turnover.

A diet rich with citrus fruit and vegetables increases alkalinity of the urine while meat creates an acidic environment hence higher protein consumption equals more acidic urine. Is this a negative in a normal healthy individual? Possibly it could be indicative of other issues or conditions but this article contests that that is it necessary to eat this diet for enhanced health/ weight loss etc. Well not really. Food enters the nutritional tract with an acidic pH due to stomach acid anyhow so regardless it really matters what it is carbohydrate, protein or fat. These stomach acids are neutralized by juices from the pancreas turning the food alkaline. Certain foods leave something called ash which affects the acidity of your urine in the bladder but as the bladder is a storage compartment for urine it plays no role in pH of the body.

On the positive side- encouragement to eat more fruit and vegetables is always a good thing. However, there are a number of caveats in this nutritional programme. Firstly, it minimizes protein consumption. Secondly, quality fat consumption becomes hard. Thirdly, it limits food choices (which may be necessary for weight loss) but ignoring one fruit or vegetable for another is lunacy.

It will work for weight loss in the same way that a lot of diets work. It limits consumption and food choices. The body will not get sufficient protein to maintain lean muscle mass. Therefore the body starts to use it’s own muscle mass for energy. As the body is crying out for energy it will still burn stored body fat but the ultimate result is that the weight loss creates a smaller but fatter proportionally individual.



Published by ianmellis

Ian Mellis MSc. CSCS is the co-founder of Results FAST ( in Ware, Hertfordshire. Specialising in athletic development, physique improvement and injury rehabilitation he provides personal training, strength and conditioning and nutrition coaching for motivated exercisers and those looking to make a long term change to their health, fitness and performance.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: