If this is your first time visiting the site, then welcome to Keto Sister.  Please start at the beginning with the Keto Beginners series that began on January 1: click HERE.

If you are a returning reader, welcome back, friend.  This post continues a series on problems that people encounter on their keto journeys.  The first post was a guest post that discusses the ins and outs of determining the right amount of protein to eat for your body (see HERE).  The second post confronts low limits on carbohydrate intake for those who may need to eat a little more carbs (see HERE).  This week, I want to address the issue of fat consumption.

A ketogenic diet implies that a person is producing ketone bodies because carbohydrate intake is limited to the point that some of the body’s needs that were fueled by glucose have been replaced with ketone bodies (interchangeably called fatty acids).  The fat that a person who is ketogenic eats and the fat on his or her body is converted into ketones.  But there are different ways to be in ketosis and not all of them are good for you.

Ways to Induce Ketosis

  1. When the body has run through its glucose stores, it begins to utilize ketone bodies.  While some people need a couple days to deplete their glucose stores, those who keep their carbohydrates more moderate may go to bed out of ketosis and awaken in the morning in ketosis.  Many folks vacillate between the two states daily without even realizing it.  Ketones are a natural fuel substrate for the body and their use is a regular part of fuel partitioning, to switch to ketones when glucose is absent.  This is a good way to induce ketosis.
  2. It is not uncommon to produce ketones when you are dehydrated.  Sometimes when dehydrated, test strips register higher amounts of ketones.  The side effects are serious: emergency room and IV fluids could be part of the picture.  One way to induce dehydration is to drink too little liquid and eat few foods with natural water in them (vegetables and fruits).  Another way is to reduce carbohydrates without also balancing electrolytes. Carbohydrates help the body to maintain hydration because they are stored in the body with water.  Sugar is hydrophilic, which means that if you put water and sugar together, the sugar will cling to the water.  Thus, in the body, carbohydrates and water go together.  This is why water weight is often the first to go when a person loses weight!  As Lyle McDonald explains in Body Recomposition:

“Carbohydrate (stored in your muscles and liver as glycogen) is accompanied by a good bit of water. For every gram of glycogen stored, you store anywhere from 3-4 grams of water with it.”

It is very common among ketoers to hear that someone has lost 10 pounds of weight in the first week.  Most often, this is a little fat accompanied by a lot of water.  This is fine the first week, but balancing electrolytes and maintaining hydration is important to feeling well overall.  Thus, dehydration is not a good way to induce ketosis.

  1. Undereat, fast or starve. A ketogenic diet mimics starvation.  It reduces insulin levels so that the body is able to access its fat stores without actually requiring a person to starve.  However, actually starving is one way to induce ketosis.  The reason this is significant is that it does not require an individual to eliminate all carbohydrates from the diet.  Ketosis can be induced if total calories are low enough, even if the person is still eating carbs.  However, undereating or starving oneself is a great way to downregulate the metabolism and create a host of long term problems with which no one wants to contend.  Needless to say, this is not a good way to induce ketosis.
  2. Eat a High Protein Diet. The energy sources for the body are glucose (from carbohydrates) and ketone bodies (from fats).  To drop excess stored body fat, a person needs to either reduce dietary carbohydrates or reduce fats.  There are benefits to reducing carbs rather than fats (see HERE), but one or the other can work for most people to mobilize fat stores, though eating low fat often requires the person to cut calories where as this is not a necessity on a low carb diet.

However, an approach called “protein sparing modified fast” has become quite popular and is being utilized for quick fat loss.  The effectiveness of this approach has been tested and documented in the scientific literature for various populations (see “Protein Sparing Modified Fasts” below in References).  It requires that a person eliminate all carbohydrates and added fats in the diet, which in turn induces ketosis.  In essence, this is a high protein diet.  On a temporary basis, eating a high protein diet helps the body drop body fat very quickly.  This is as far as most people consider when they want to lose weight.  Fast and effective must mean it is also good for you, right?  WRONG.

Can doing something for just a few weeks have negative long term consequences on the body?  A b s o l u t e l y.

The thyroid gland is the master metabolic hormone in the body.  As I discussed in the post titled “Keto Problems: Too Little Carbs,” this gland is dependent upon total dietary intake (eating enough calories) and also needs glucose for optimal function.  The thyroid is very sensitive and it notices when total calories change or when it loses one of its two sources of fuel.  One study put people on five different diets for five days each (Davidson & Chopra, 1979): 2100 calorie (designed to maintain current weight) diet with 20% carbs (105 grams carbs), 2100 calorie with 40% carbs (210 grams carbs), 2100 calories with 80% carbs (420 grams carbs), 4000 calorie diet with 20% carbs (200 grams) and 4000 calorie diet with 40% carbs (400 grams).  The diet with the lowest carbs, 2100 calories and 20% carbs, showed a significant decrease in triiodothyronine, the active form of thyroid hormone also called T3.  There was less of a difference between the 2100 calorie diets with 40% and 80% carbs respectively.  There was no difference between the T3 levels for those who followed the diets with an excess of calories, despite the differences in total calories.

The purpose of a low carb diet is not to eliminate any dietary source of calories, but rather it allows for a similar or even higher intake of calories while still allowing for a reduction in insulin levels and body fat stores.  A person can mitigate the negative effects of lowering carbohydrates long enough to induce ketosis by increasing intake of dietary fat and then long term by eating enough fat.  The body converts approximately 10% of fat to glycerol for use as glucose in the body, so eating fat is one way to increase glucose in the body.  Crazy but true!  Also, increasing fat alerts the body that there is not a shortfall of energy but rather an abundance of energy as fat.  This is one way to ensure that the body upregulates its machinery to process and utilize fats for fuel (called keto adaptation).  Once the body effectively utilizes fats for fuel, it will use dietary fats and when they run out—like overnight while you are sleeping—it will access body fat stores.

Unfortunately, the fear of dietary fats is deep seeded in many people.  The idea of reducing carbohydrates is easy to understand, especially when water weight is lost so quickly after reducing carbs.  But a ketogenic diet is optimal when a person both decreases carbs AND increases fat intake.  Food is more than just calories or macronutrients.  It provides powerful signals to the body that alert it to whether the conditions are safe for reproduction (endocrine system) and safe to mobilize body fat stores (metabolism).  When food is plentiful, hormonal function and the speed at which body fat are burned are optimal.  When food is in short supply, such as a diet that limits carbs and fats, hormones very quickly imbalance to try to compensate for the perceived famine.  Cortisol, the stress hormone, elevates to increase energy so you can hunt and find food.  And the metabolism slows way down so that you do not burn your fat stores as quickly since the faster your metabolism runs, the sooner it thinks you will die.

This may sound dramatic, but consider how to the body operates.  It does not know that you pass food up by choice in favor of bikini season.  It does not know that you are running on a treadmill or biking on a stationary bike.  It believes that you are starving to death and running from a lion, and the body’s decisions to upregulate or downregulate its machinery are protective mechanisms hard wired into us for survival.

The best way to avoid accidentally activating these mechanisms is to do the following:

  1. Eat enough food. If you are uncertain how much food is enough for your body, start with this post on determining the right amount of food to eat for fat loss: The “Right Way” and “Wrong Way” to Diet (http://ketosister.com/deficit-the-right-way-and-wrong-way-to-diet).  I personally hit my goal weight of 140 pounds by increasing my dietary intake rather than setting a deficit, but most people do not believe this will work for them.  Here are reports of two others who did the same thing and their results:  Dave Asprey and Jason Whittrock.
  2. Stay away from gimmicks that promise quick fat loss. Fat fasts, egg fasts, protein fasts, etc. can be effective for some people.  If you have any hormonal problems, however, you should avoid these strategies and simply trust the process.  When you are eating the optimal balance of foods for your body, gimmicks are not necessary.

Remember, we are eating a low carb diet for health, not just to look good naked.  Okay, we want to look good naked too but you don’t have to attempt this at the expense of your health.  Want to know more about how to eat enough to satisfy your hunger, fuel your hormones and keep your metabolism stoked, and most importantly to be healthy, contact me at airia@ketosister.com.  Thanks for reading!


Davidson MB, Chopra IJ. Effect of carbohydrate and noncarbohydrate sources of calories on plasma 3,5,3′-triiodothyronine concentrations in man. J Clin Endocrinol Metab. 1979 Apr;48(4):577–581.

McDonald, L. (2008).  Body Recomposition.  http://www.bodyrecomposition.com/fat-loss/what-is-body-fat.html.

Protein Sparing Modified Fasts:

Adams KF, Schatzkin A, Harris TB, et al. Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old. N Engl J Med. 2006;355:763-778.[PubMed]

Avenell A, Brown T, McGee M, et al. What are the long-term benefits of weight reducing diets in adults? A systematic review of randomized controlled trials. J Hum Nutr Diet. 2004;17:317-335. [PubMed]

Bravata D, Sanders L, Huang J, et al. Efficacy and safety of low-carbohydrate diets: a systematic review. JAMA. 2003;289:1837-1850. [PubMed]

Koeck E, Davenport K, Barefoot L, Qureshi F, Davidow D, Nadler E. Inpatient weight loss as a precursor to bariatric surgery for adolescents with extreme obesity: optimizing bariatric surgery. Clin Pediatr (Phila). 2013;52:608-611. [PubMed]

Sargrad K, Homko C, Mozzoli M, Boden G. Effect of high protein vs high carbohydrate intake on insulin sensitivity, body weight, hemoglobin A1c, and blood pressure in patients with type 2 diabetes mellitus. J Am Diet Assoc. 2004;105:573-580. [PubMed]

Wilke W, Walters J, Hoogwerf B, Reddy S. The protein-sparing modified fast for obesity-related medical problems. Cleve Clin J Med. 1997;64:242-244. [PubMed]