What’s the best time of the month to start a diet?

Almost all diets work. Perhaps not the really crazy ones, but any diet that calls for an increased awareness around carbs, fats, calories and portion sizes will help you to lose weight – in the short term anyway. When a diet ‘stops working’ it is more often than not a compliance issue. With this in mind, the next logical question is, “Are there ways to improve adherence for better long term weight loss results?” Absolutely!

Firstly, choose a diet that is easy to sustain.  Secondly, choose the best time of the month to start your diet. This has nothing to do with starting on the 1st of the month, or on a Monday, or after a holiday, or once your salary cheque has cleared.  Nope. It has EVERYTHING to do with your menstrual cycle, ladies. Taking the ebb and flow of your monthly hormones into consideration could make the difference between getting off to a great start or throwing in the towel 3 days into your diet. Why? Because estrogen and progesterone have a massive impact on energy levels, exercise performance, hunger, fuel utilization, metabolic rate and cravings.

Let’s first explore diet choice. We know that diets that severely restrict fat or calories can leave one constantly hungry and unsatisfied. Doesn’t sound appealing or sustainable does it?  A better option is to reduce carbs to bring down insulin levels and optimize fat burning. Eat only when you are actually hungry to control calorie intake. Healthy fats in the appropriate quantities are good for you, so don’t be fat phobic.  Protein is the most satiating of the macro nutrients, so be sure to include enough meat, chicken, eggs, fish and the like in your diet.  Fill your plate with vegetables and salads. The fibre and water content will keep you feeling full for longer.

Now let’s look at timing. To get a better understanding, we first need to get some insight into the nitty gritty workings of the female body. Generally, a naturally menstruating women will have a 28 day cycle or thereabouts.  The cycle is broken up into two main phases:

  1. the follicular phase (day 1 to 14) and the
  2. luteal phase (day 15 to 28).


For clarification, day 1 is when your period starts and day 14 (mid cycle) is when an egg is released from the ovary and ovulation occurs. During the follicular phase estrogen (estradiol) rises and is the dominant hormone. In the luteal phase estrogen drops off and progesterone starts calling the shots.


The graph below, taken from Lyle McDonald’s website www.bodyrecompisiton.com, illustrates this.






Besides regulating fertility, estrogen and progesterone have other effects on our body that impact on how we feel. Some women breeze through their cycles while others really struggle. See table below.


First two weeks of cycle (Follicular phase)

Dominant hormone: Estrogen

Last two weeks of cycle (Luteal phase )

Dominant hormone: Progesterone

·      Hunger is controlled

·      Minimal cravings

·      Physically stronger

·      Energy and motivation good

·      Stable moods

·      Feeling of wellbeing

·      More insulin sensitive

·      Good muscle recovery


·      Appetite increases

·      Cravings intensify

·      Water retention/bloating

·      Physically weaker

·      Energy and motivation levels low

·      Moods can become unstable

·      Potential for headaches and cramps

·      Less insulin sensitive

·      Slower muscle recovery


Taking the above into account, it would clearly be best to start a diet in the follicular phase – perhaps just after your period has finished. You will be in a better frame of mind and since the first week of a diet is always the hardest, this could really help with motivation and willpower. You will have at least 2 weeks to get into the swing of things and create better habits before PMS, increased hunger, low moods and cravings set in towards the end of the luteal phase. Knowing what to expect and why it is happening is helpful and allows one to make a plan to get through it.

For example, the reason appetite increases during the luteal phase is because one’s metabolic rate increases.  So, instead of going off the rails by chomping down on a hamburger and chips, rather be well prepared and allow yourself to eat more-healthy low carb food and a little more fat.  In the event that cravings get too much to handle in the days leading up to your period, opt for 1 or 2 blocks of quality dark chocolate. This is far better than trying to hold out and then eventually caving and eating an entire slab in one sitting.

Supplement tip:Taking a vitamin B complex, magnesium and chromium can help to control the symptoms of PMS and cravings.

Another point to note is that, due to a decrease in insulin sensitivity, one’s body doesn’t handle carbs as well during the luteal phase. You are better advised to keep carbs to a minimum and rather consume a little extra fat to help with cravings and satiety. Save the healthy “orange list” carbs like butternut, sweet potato and carrots for the follicular phase when your body handles them better because you are more insulin sensitive at this time.

Diet tip:In the follicular phase include more starchy veggie carbs and lower your fat consumption.  Then, in the luteal phase, swap them around by reducing carbs and adding more fat.

Women tend to feel really good during the follicular phase. Their mood is stable and they have more energy.  It’s later, in the luteal phase, where things tend to go downhill and we just feel blah? The best time to ace your workouts is therefore in the follicular phase and early in the luteal phase. Granted, you may want to be over your period first, especially if you are one of those unlucky ladies who require the “big guns” when it comes to sanitary products.  Want to push for a personal best? Do it in the late follicular phase and more specifically just before ovulation when a woman’s testosterone peaks and strength increases.

Exercise tip: Don’t make yourself hungrier and more tired by upping the duration or intensity of your workouts during the luteal phase. Use this time to take it down a notch and ‘de-load’, especially during the late luteal phase (week 4). As an alternative, focus on flexibility, form and technique as well as gentler forms of exercise like walking and swimming.

Mix things up a little and keep your body guessing.  Vary carb and fat amounts during the different phases. Eat a little more when you feel hungrier and less when appetite is under control. This approach has been shown to be very beneficial for maintaining a good metabolic rate when losing weight – not to mention the positive effect it seems to have on adherence to a diet over the long term. Work with the natural rhythms of your female body and give it what it needs at the different times of the month. So, next time you want to start a diet or get back onto the wagon, first take a moment to work out where you are in your cycle and plan your start date accordingly. There are great free Apps available for charting your cycle.

Note:If using contraception that artificially regulates your cycle or prevents menstruation completely, the above may not be applicable.

Article written by Nicky Perks for Lose It magazine (Volume 27)

Have you checked out my opportunity page of this blog yet?  

About Nicky Perks

Passionately sharing information about the paleo/primal, high fat/low carb lifestyle that will rock your world! I am on my own journey to good health and a slim body. My goal? To enjoy the ride as life on this beautiful planet is just too short to do it any other way.

Posted on February 18, 2019, in Primal 101 and tagged , , , , , . Bookmark the permalink. Leave a comment.

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