• Katie Chaplin

The truth about Caffeine

Is it harmful?Or can it actually HELP you achieve your goals?

Caffeine is one of those subjects that massively irritates me. It seems that people that don’t really have a clue normally have the strongest opinion about it.

Caffeine, in moderation, is NOT harmful- it has been shown to enhance mental and physical performance and reduces effort perception (1), not to mention the obvious decrease in fatigue.

Of course like anything if you overdo it you are going to have side effects but as a vague guideline it is recommended that you do not consume more than 400mg a day (2) ( 4 cups of coffee) but this is still, as I said, vague. An Important note here is that it is likely you will be recommended to avoid caffeine altogether if you are pregnant or have a certain heart problem (or in some anxiety cases as it may ‘gee you up’ too much), but other than these cases you should be fine.

Why I bring the subject up of caffeine is that is a useful tool on a diet during energy slumps, you’ll be surprised how many times you think you are hungry when actually you are tired. Do you feel yourself reaching for the biscuits at about 4pm? This is often because your body is fatiguing at this point and in order to keep itself awake it craves something that will give it an immediate energy hit, which it will get from refined carbohydrates such as biscuits. Ideally when you have this feeling you would rest, but let’s be realistic, in most cases you are not going to be able to have a nap at work! If you have a caffeine hit you should quickly find that your carb cravings are curbed.

Caffeine has also been seen to increase your metabolic rate (3,4)- largely because you tend to be more active once this is consumed.

In my opinion this is why things like raspberry ketones have some success with certain people - they often put a high caffeine content in these products, which pushes you through the afternoon and prevents cravings, as well as keeping you more physically active. So you're better off having a coffee , then paying through the nose for products such as these.

Caffeine is also constantly recommended as a supplement pre workout to increase mental and physical alertness - how many times have you not gone to the gym because you felt too tired? Whilst I am not advising you to hammer 4+ coffees a day, do not listen to those that lecture you for having a cup!


1. Glade MJ. (2010) Caffeine- Not just a stimulant. Nutrition, Volume 26, issue 10, pages 932-938.

2. Nawrot et al (2003) Effects of caffeine on human health. Food Addit Contam, Jan; 20(1):1-30, DOI 10.1080/0265203021000007840.

3. Belza et al (2009) The effect of caffeine, green tea and tyrosine on thermogenesis and energy intake. Eur J Clin Nutr, Jan; 63 (1):57-64.

4. Astrup et al (1990) Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers. Am J Clin Nutr, 1990 May; 51 (5); 759-67


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