How much cardio is too much?


Does your morning Bulletproof coffee break your fast?

The answer to this and other questions – for example, How much cardio is too much? And should you be worried about elevated LDL on low carb? – in this week’s Q&A with Dr. Andreas Eenfeldt:

Does my morning coffee break my fast?

I have been on an LCHF diet for over a year now, and have lost over 50 pounds (23 kg). One of my strategies has been condensing my eating to 6 hours (lunch and dinner) and fasting for 18 hours. This has become easy for me, but there is one aspect that I am not sure about.

For the past 12 months, I have been drinking coffee with a slice of grass-fed butter with a tablespoon of MCT oil (a la Bulletproof coffee). Admittedly, I feel fantastic and it keeps any hunger at bay until lunch. However, as the coffee is pure fat (there are no carbs and no proteins) and it doesn’t trigger my insulin, would you say this is breaking my fast or not?

My own opinion is no, as my primary objective is to reduce my insulin resistance, and my current schedule does not trigger my insulin for those 18 hours.

I would love your thoughts on this.


It does slow weight loss somewhat, but if you’re happy with the effect anyway and like it… why not continue?

Regarding fasting or not – it’s close, but a slight cheat. ;)

Andreas Eenfeldt

How much cardio is too much?

Hi Dr. Eenfeldt,

I am a month into my keto diet and feeling great! Both you and Dr. Fox seem to discourage too much cardio. Dr. Fox especially said women should not do too much cardio (I posted this question to him several weeks ago but got no reply). So where do you draw the line? An hour a week? Three hours a week? 5 miles a week? My doctor still recommends 30 minutes a day, 3 to 5 times a week.

Thank you for your reply!

I think that’s very individual. I think Dr. Fox has the perspective of maximizing fertility and in those cases relatively low amounts may often be negative. In other situations I think several hours per week or even more could be fine, if it makes you feel good.


My LDL is too high after six months of LCHF!

Hi Dr Andreas,

I have been LCHF for six months now and have lost almost 20 lbs (9 kg)! I feel amazing. However, I had my lipids tested and my LDL came in at 142 mg/dl (“normal” range 0-99 mg/dl). My triglycerides, HDL and VLDL all were within the ranges listed as normal. My total cholesterol was 272 mg/dl (normal 100-199 mg/dl). This test was done on a fast. Now my doc wants me to cut back on saturated fats! Shall I move towards plant-based fats for more of my cooking? I really don’t want to go back to my old habits, but I am not sure what direction to go. Please help!

Thank you,

Hi Mara!

Very doubtful if that’s anything to worry about. About half the adult population is above that “normal” range, so how normal that is can be questioned, but it’s surely a good cutoff for people selling cholesterol lowering drugs.

Here’s more on how to think about and handle high cholesterol levels on LCHF:

Low-carb and keto side effects

Andreas Eenfeldt


Low Carb for Beginners

More Questions and Answers

Many more questions and answers:

Low-Carb Q&A

Read all earlier questions and answers – and ask your own! – here:

Ask Dr. Andreas Eenfeldt about LCHF, Diabetes and Weight Loss – for members (free trial available).

More About LCHF and weight loss

  • My success story with Kenneth Russell
  • My success story with Chuck Hicks
  • How to motivate your patients
  • The hidden costs of medications

One comment

  1. Linda
    I am confused about my macros. I figured out what they should be and when I enter my bulletproof coffee, I have used up
    Almost all of my fat for the day.

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