Controversial carbohydrates are back in the spotlight! Have you heard about the no carbs 5pm rule?
Does timing of carbohydrate consumption matter in weight loss? Is there truly a magic hour involved? Armed with my passion for evidence-based nutrition and love for delicious carbohydrates, join me as I set out to unravel the truth. Let’s start with dissecting how the trend started, the scientific evidence, the pros and cons, and a summary.
Firstly, what is the no carbohydrate after 5pm trend?
This trend was initiated by a book with the same name written by Joanna Hall (Hall, n.d.) in 2005 that promises 5 inches lost from your waist by following a 28-day plan of cutting carbs after 5 pm, the magic hour.
Is there science behind it?
Let’s first dismantle the concept. Firstly, there is an emphasis only on one nutrient, carbohydrates, which is NEVER how nutrition works. In fact, the Australian Dietary Guidelines, our go-to source for healthy eating advice, recommends that individuals consume ALL five food groups. Even snack foods are allowed as part of a healthy diet but remember, having a whole row of Tim Tams in a day is not the way to go! Carbohydrates causing weight gain ONLY happens when we have too much carbohydrate at which point it converts to fat and gets stored.
Is 5 pm a magic number for weight loss then? Limited research has been conducted around this trend to give us any certain evidence for the benefits or limitations. Accredited practising dietitian, Dr Alan Barclay, mentioned in an article for Nine News Australia, that there is no scientific evidence relating timing of carbohydrate consumption to weight loss in any way.
What is misleading is that reducing carbohydrates CAN cause some weight loss in the form of water. The carbohydrate stores in our body are known as glycogen. Glycogen stores additional water with it. As our body cannot store infinite amounts of glycogen, we need to continually top them up by eating carbohydrates. When we stop eating carbohydrates for a long time, our glycogen stores run out and with it, we lose water weight.
Pros
Although not many, one benefit from the focus of 5pm could be the reduced consumption of some snack foods or refined carbohydrates. As they are typically high energy foods, reducing snacking at night may decrease your total calories (energy).
Cons
Unsurprisingly, this approach has a longer lists of negatives for us to consider. Firstly, we need to make the distinction that not all carbohydrates are equal. Simple and refined carbohydrates such as sugary treats or drinks break down and release energy quicker. Too much in the long run will cause the excess energy to be stored. Complex carbohydrates break down slower keeping us full for longer. These carbohydrates also have fibre which is very important for gut health. By avoiding all carbohydrates, we eat lesser complex carbohydrates which reduces our fibre intake and leads to the risk of developing constipation.
The bottom line: Eating carbohydrates at night will NOT cause you to gain weight if the calories are within your energy requirements. It really comes down to what other macronutrients (carbs, fat and protein) you are eating throughout the day.
You shouldn’t be expecting any sort of miraculous results if you are eating poorly during the day and avoiding carbohydrates at night. You will gain weight if you are eating excess calories to what your body requires regardless of the timing.
Remember to adjust your carbohydrate intake according to your activity levels and listen to your own internal cues (hunger/fullness signals). Carbs are not the enemy for weight loss. You can eat carbs and still lose weight.
If you are unsure about what to eat or how carbs can be included for weight loss, book in with me so we can develop a tailored plan for you!
