This just in: Not eating enough fat makes you fat.

Whatever making you ‘fat’ means, but the truth of the matter is that by being conscientious about fat intake (on the restrictive side) makes your body more likely to store fat.  Yippee!  Oh, you mean that wasn’t your intention?  Oh, then maybe you need to meet Mr. Leptin.

Leptin acts on receptors in the hypothalamus of the brain where it inhibits appetite by (1) counteracting the effects of  neuropeptide Y (a potent feeding stimulant secreted by cells in the gut and in the hypothalamus); (2) counteracting the effects of  anandamide (another potent feeding stimulant that binds to the same receptors as  THC ), and (3) promoting the synthesis of  α-MSH , an appetite suppressant. This inhibition is long-term, in contrast to the rapid inhibition of eating by  cholecystokinin (CCK) and the slower suppression of hunger between meals mediated by  PYY3-36 . The absence of leptin (or its receptor) leads to uncontrolled food intake and resulting obesity. Several studies have shown that  fasting or following a  very-low-calorie diet (VLCD) lowers leptin levels.

Okay, so that means that low amounts of leptin cause increase eating and increase fat storage.  Only leptin and insulin are currently known to regulate fat storage in the body.  It only makes sense that the body would want to store more fat if intake is low–just like having water retention when fluid intake is low.  The body needs fat to perform many functions in the body:

• The brain is 60% fat.
• All neurons are coated in a myelin sheath–this is fat.
• All cells have a phospholipid layer–lipids are fats.
• Fats regulate the feeling of satisfaction after eating.
• Fats slow the digestion of carbohydrates, which promotes more stable blood sugar levels.
• Fats play a role in mood regulation.
• Fats are critical for hormone production.
• Fats are critical for fertility (both intake and body stores).

So you can see that fats have many things to do before they want to go hang out in your body to make you ‘fat’.  Unless you are being restrictive with fat (which I can say the majority of the clients I’ve seen are–there is a good chance you are too), which just makes your body need to store it for future use.  People typically overestimate their fat intake.  The body needs (according to biochemistry, not some fad diet) approximately 30% of calories to come from fat.  If the typical intake is 2000-2500 calories per day, this would be 60-80 grams of fat per day.  That is an amount that takes work–you have to be deliberately adding fats to your foods or there is no way you are getting this.

To review, intake of fat increases leptin levels.  We want higher levels of leptin because lower leptin levels signal the body to store more fat.  The body definitely needs to have a healthy level of fat stores, but my guess is most people reading this are not looking to increase their current level of fat stores.  Here are some things that affect leptin levels:

Leptin levels decrease after short-term fasting (24–72 hours), even when changes in fat mass are not observed.

Restful sleep (i.e., 8–12 hours of unbroken sleep) can increase leptin within normal ranges.

Serum levels of Leptin are reduced by sleep deprivation.

Increased by perceived emotional stress.

Decreased by testosterone and increased by estrogen.

Chronically affected by exercise training; it decreases leptin levels.

 

I believe I have a post on good and bad fats, but if not, I will write one.  Do not be fooled–all fats perform the listed functions in your body.  Here are some great sources of fats:

1. Butter
2. Cream Cheese
3. Mayonnaise
4. Avocado
5. Sour Cream
6. Peanut butter
7. Olives and Olive Oil
8. Nuts and seeds
9. Fried foods
10. Desserts such as cookies, brownies, cake, etc.

I wish I didn’t have to say this, but I do based on my experience with clients:  none of the above listed sources of fats should be purchased in the ‘low-fat’ or ‘light’ versions.  There are not actually that many sources of fats, so do work to include these things in all meals and preferably snacks as well.  You really need at least 8 added fats in addition to the fats in your other foods.  So if your cheese on your sandwich has fat, you still need to add mayonnaise–get it?

I want to be clear this fat-love is coming from someone who was terrified of fats back in the 90′s.  That was my major restriction, I think due to its unfortunate name.  Now I can see what a difference eating fats makes.  I am satisfied after meals (versus being full, but still looking for something else to eat), I do not think about food between meals, and I even believe my body stores less fat than it used to when I was restricting it and exercising like crazy.  My brain is definitely better now.  Anyway, I encourage you to honor your body’s needs for fat–otherwise you will face the repercussions of working against your biological needs.  Believe me, that is not going to be the outcome you’re looking for.

P.S.–A big “thank you!” to Lita for reminding me that this blog is being read and is helpful to others. XOXOXO

References:

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• Weigle D, Duell P, Connor W, Steiner R, Soules M, Kuijper J (1997). “Effect of fasting, refeeding, and dietary fat restriction on plasma leptin levels”. J. Clin. Endocrinol. Metab.82 (2): 561–565.  doi :.  PMID .
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