Eating for “Energy”

People often come to me saying they want to learn how to improve their nutrition so they can lose weight and “have more energy”. Have you ever stopped to think about what this “having energy” really means?


Does “energy” mean jumping around in fields with rainbows??

Calories are a measurement of energy. Weight loss requires a net loss of calories (if calories eaten is less than calories burned, you will lose weight). Therefore, weight loss necessitates that you actually reduce the energy you’re taking in. This is not what people expect to hear. That is because when people say they want “more energy”, they’re looking for something other than the scientific definition of energy.

So what is it that people are actually asking for when they say they want to feel energetic? I’ve determined that it’s a couple different things:

  1. A nutrient-dense diet that will provide all the essential vitamins, minerals, and phytochemicals to maximize performance
  2. Consistent blood sugar throughout the day, without significant dips that leave you feeling sluggish even when your overall calories are adequate to fuel the body

The first point is easy to address: eating plenty of fruits, vegetables, and whole grains will get you the nutrients your body needs. You can’t just opt out of these foods, as we’ve discussed. The cure for the second point also addresses the first. Keeping blood sugar consistent necessitates eating those fruits, vegetables and whole grains; but there’s more to it than just that – we need to also consider timing, amount and specific food selections. To describe, we need a little biology lesson.

What is blood sugar?

Blood sugar is just that: sugar in your blood. The sugar comes from any carbohydrate that you eat, whether it’s a piece of candy, a potato, brown rice, or any other food with carbohydrate in it. You see, carbohydrates of all types are made up of little sugar molecules linked together in chains. During digestion, your body chops up the chains into the smaller sugar molecules to be absorbed into your blood stream, where it is circulated around your body and used by cells . Glucose (blood sugar) is how your cells make energy, so it’s really really important to have some around!

But your cells can’t just suck it up on their own! When your blood sugar starts to rise after a meal, your pancreas releases insulin. Insulin is a hormone that allows your cells to take up blood sugar in order to do things like making your muscles contract, absorbing certain nutrients, even thinking. Insulin is really important, so remember it for later.

What happens if I haven’t just eaten?

So you’ve got all that blood sugar from your meal, then your cells take it up. Eventually you’ll use it all, right? Right. Never fear! You’ve got stored energy for situations like this – your fat. Your body is able to convert fat into energy, but it’s a slower and less efficient process. Remember that. No carbohydrate = slower, less efficient process of making energy. 

When do things go wrong?

In a healthy person, blood sugar can get low by two main mechanisms:

  1. Fasting, especially with carbohydrate restriction: If you haven’t eaten in a long time, your blood sugar will be lower than if you have eaten. If you haven’t eaten in a long time, you’re more likely to have dangerously low blood sugar. Have you ever dieted or tried to cut out carbs? Do you remember how stupid you got? That’s because you didn’t have adequate glucose to fuel your brain efficiently. You want that, trust me.
  2. Reactive hypoglycemia: If you eat a meal that is very high in quick-absorbing carbohydrates, your body may accidentally pump out too much insulin. This will result in your body taking up that blood sugar pretty quickly, causing a rapid fall of blood sugar to levels lower than normal, more quickly than your body can start converting fat to energy. You know that post-pasta dinner crash? This is where that comes from.

How can I stabilize my blood sugar for sustained energy?

  • EAT THREE MEALS A DAY: If you’re not doing this already, we are in a fight.
  • Breakfast like a king, lunch like a prince, dinner like a pauper: (so sexist, sorry ladies). I see a lot of people who come to me with good intentions of minimizing daily calories. They start out eating almost nothing for breakfast, have just salad for lunch, and then go crazy when they get home from work. Their blood sugar is just so low at that point that carb cravings kick in (as they should) and then their diet goes straight to hell. Shift those calories up in the day: get a good solid breakfast, a sizable lunch, and keep dinner a little bit smaller. You’ll have plenty of the nutrients essential to sustain your blood sugar throughout the day.
  • Eat some carbohydrate with every meal: Some being the operative word here. I normally see people eating either no carbohydrate at all, or eating way way too much. Follow the Plate Method for a good guideline – make 1/4 of your plate a carbohydrate food. This way you will never have too little, and never have so much that you get the spike and crash of reactive hypoglycemia.
  • Choose complex carbohydrates: You want that 1/4 plate to be full of complex carbohydrates. Think whole grains and starchy vegetables instead of white bread/rice/pasta, or sugary things. A generally good rule is that the sweeter it is, the simpler a carbohydrate it is, the less work your body has to do to break apart those chains, and the quicker it can be absorbed. Quick absorption = blood sugar spike, possibly leading to reactive hypoglycemia.
  • Pair carbs with protein and fiber: These nutrients take longer to exit the stomach, slowing down the absorption of carbohydrate and making the absorption of carbohydrates a slower, more gradual process. If you follow the plate method this will automatically happen at meals, but it applies to snacks too. Pair fruit with string cheese or nuts, crackers with peanut butter, granola with yogurt, etc.
  • Avoid sugary foods, especially alone (hello, soda drinkers!!): If we know that simple carbs, i.e. sugars are absorbed really quickly, and we know that fiber and protein slow down absorption, what do you think happens when you take sugar, mix it with water, and consume it with nothing else? HUUUUUUGE blood sugar spike. This goes for sugar, juice, and other sugary foods. You’re going to get that big spike and may experience reactive hypoglycemia.
  • Read an upcoming blog post about meal planning for stable blood sugar: It’s gonna be a doozy, I promise you. Stay tuned/subscribe to the blog for updates on when it’s posted. I’m on a pretty good roll right now so it might even be before Memorial day 😉


This topic can get very scientific and detailed pretty quickly, but try these tips to help you stay energetic throughout the day, even while losing weight. And of course, don’t forget exercise, sleep, and mental health as important factors when it comes to fighting fatigue!



9 responses to “Eating for “Energy”

    • Thank you! It can be hard to tell if I’m making sense after writing for a while, I had to take a couple days off between writing this post, clarifying, and posting. I’m glad to hear it worked 🙂


  1. So in point 1. under “When do things go wrong” did you mean to type ” You DON’T want that, trust me” instead ?


  2. Ah! I thought that sentence “You want that, trust me”, was follow on to “do you remember how stupid you got” and said that you probably left out the Don’t. I see that I was missing one crucial sentence in between those two sentences !


  3. I love how you take really complex and scientific information and simplify it. It can be difficult to explain things so that the “main” point is understood clearly without getting into all the nitty gritty. I am finding that the more nutrition classes I take, the harder it actually is for me to explain things to friends and family! I look forward to your next post on meal planning and appreciate the science behind all your posts!


    • Thanks! I’m so glad you like it. I think the more time you spend with patients, the easier it will get. It’s soooo tempting to get down into a scientific rabbit hole, but you learn pretty quickly what will make people lose interest (I think/hope – haha)


  4. Pingback: Diabetic exchange meal planning – not just for diabetes! | How to Eat, R.D.·

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