Right place, right TIME!
The Importance of Nutrient Timing
When it comes to talking about nutrition the focus always turns to the topic of how many calories you eat, or the ongoing low fat vs. low carbohydrate debate. However, there is a lack of attention going towards the timing of food. Understanding how the body reacts to different foods at different times is crucial in maximising your progress and performance. Poor nutrient timing can cause unwanted fat gain even when consuming fewer calories, and it can have a massive impairment on your performance. It is important to note that what types and times of nutrients will vary depending on the person and their goals, and it is for this reason that I will divide this subject up over multiple posts to cover all aspects of the topic.
This first post will focus on carbohydrates timing when aiming for fat loss. Both carbohydrates and fats have been given bad reputations in recent times and depending on who you speak to you can hear two completely different stories. One person may tell you that eating a grain of white rice is going to put on masses of fat, and another may say that eating a gram of fat is going to block your arteries and give you a heart attack. My standpoint is somewhere in the middle. This is because I first learnt about the importance of carbohydrates with their uses towards athletes and exercise, then later learnt about the damage they can do when used incorrectly.
When discussing carbohydrates and the timing of them, we must talk about insulin. Insulin is a hormone released from the pancreas, a fish-shaped organ in the belly. It is an absolute powerhouse of a hormone and has numerous roles within the body. One of those roles is the maintenance of blood glucose (sugar) levels. When you consume carbohydrates, or even have them in your mouth, insulin is released to help transport the glucose in the foods into the cells (muscle, liver or fat cells) for storage. The size of the response depends on a number of factors, one of those being the Glycemic Index (GI) of the food eaten. Now many of you I’m sure have heard the term ‘GI’ before, and it basically tells us how fast a carbohydrate is broken down and its effect on your blood sugar levels. A high GI food will spike insulin to a high level quickly, and a low GI food will cause a smaller rise for a longer period of time. Another term of importance is the Glycemic Load (GL), which helps us account for the portion size of the carbs.
Now the reason insulin is so important is because problems with this hormone can lead to serious and life-threatening conditions (i.e. diabetes), so understanding it is crucial. Insulin deposits the energy into the fat, muscle or liver, based on food timings, activity levels, when we ate last, and a number of other factors. So we need to know when and what carbohydrates need to be eaten to turn our bodies into fat burning machines.
Generally speaking, the body will always use carbohydrates for energy if they are present, as they are the fastest and most efficient form of energy, and the body LOVES efficiency. As well as this, if we are consuming more carbohydrates than are needed the body will store them away as reserves as fat! So if we repeatedly eat high GI foods we are continually spiking insulin, and therefore setting up a fat storing environment. For example, let’s take someone who wakes up, has a sugary breakfast, snacks on high GI foods throughout the day and returns home to have a high GI meal paired with lots of fats. Although they might seem like they are only having a few innocent snacks during the day, the insulin response is rapid and large. Additionally, the meal at the end of the day in combination with the snacks is putting the body in the perfect situation for fat storage. This is how to use insulin the wrong way (see figure titled ‘TIMING DONE WRONG’).
Back to the ideal. What should happen is we have our carbohydrates at two time points during the day: the morning, and post workout. When we go to sleep our bodies turn to fats as a fuel source as there are no carbohydrates present and it wants to preserve the stores of energy it has. This is why when you wake up you may have smelly breath as the by-products of using fat as a fuel cause the odour in your breath. When you wake up after using fats as a fuel, your body is much more sensitive to insulin which makes it an acceptable time to have carbohydrates. I will throw a spanner in the works at this point and say that although this is one of the okay times to eat carbohydrates, if you are aiming for weight loss, it would be better to have a high fat/high protein meal to help you throughout the day. The second time, and most important, for carbohydrates is post workout. When we exercise we deplete our stores of glycogen (stored form of carbohydrates), this results in a need for replenishment. So after we work out we have our carbohydrates which spikes the insulin, and uses the carbohydrates to store the energy into the muscles for growth and repair rather than storing it in the fat cells. In addition to this, there is also a term known as EPOC (Excess Post-Exercise Oxygen Consumption), which happens after we complete a high intensity session. When this happens our oxygen consumption is raised for a prolonged duration after the session, which creates a demand for more energy, resulting in more calories burned. This post workout window for carbohydrates is open for roughly two hours following your session, after this insulin sensitivity is decreased. Once this window is closed we reduce our carbohydrate intake and switch to low GI carbohydrates until we go to sleep and repeat the process the next day (see figure titled ‘TIMING DONE RIGHT’).
If we look at both graphs, and compare the area under the line titled ‘fat burning’ we can see the right timing has a much greater area spent in the fat burning zone rather than fat storing compared to the graph in the wrong way.
So to recap:
- Wake up in the morning in a fasted state with blood glucose and insulin the lowest
- Workout and consume carbohydrates post workout to spike insulin and drive glucose into the muscles to promote growth and repair
- Decrease carbohydrates for the rest of the day
- Repeat the next day
Next time I will cover carbohydrate timings for performance and protein timings and quantities.